Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
1. Why is scientific notation used in science?
a. because it makes it easy to write very big or very small numbers b. because all astronomical
distances are expressed in metric units c. because it makes conversions between units easy
d. because it makes conversions between distances easy
ANSWER: a
2. What is the approximate diameter of the Earth? a. 1 AU
b. 13,000 light-years
c. 13,000 kilometres
d. 1,000,000 kilometres
ANSWER: c
3. What is the average distance from Earth to the Sun? a. 1 ly
b. 1 AU
c. 1 million km d. 1 billion km
ANSWER: b
4. Which one of the following statements best describes a planet? a. a non-luminous body
b. an irregular shape
c. a body that generates energy by nuclear fusion
d. a body located at the centre of the Solar System
ANSWER: a
5. Which one of the following statements best describes the Sun? a. generates energy by nuclear
fusion
b. located 10 AU from Earth
c. orbiting the Solar System
d. located in the centre of the Milky Way ANSWER: a
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6. What does the Solar System contain?
a. the Sun, its planets, and some smaller bodies b. the Sun, galaxies, planets, and stars
c. the Sun, planets, moons, and stars
d. the Sun, planets, asteroids, and galaxies
ANSWER: a
7. lately how many times larger than the diameter of a typical planet (the Earth) is the diameter of a
typical star (the Sun)?
a. 10 times
b. 100 times
c. 1000 times d. 10,000 times
ANSWER: b
8. How does the radius of the Moon’s orbit compare to the radius of the Earth? a. It is 0.6 times as
large.
b. It is 6 times as large.
c. It is 60 times as large.
d. It is 600 times as large.
ANSWER: c
9. Which of the following is no longer considered a major planet? a. Mercury
b. Uranus
c. Pluto
d. Saturn ANSWER: c
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
10. In the diagram, what is the diameter of Mercury?
a. about 240 km
b. about 2400 km
c. about 24,000 km d. about 240,000 km
ANSWER: b
11. If the distance from the Sun to the Earth is represented by roughly 15 metres, then what would
the distance from the Earth to the Moon on the same scale be?
a. about 30 metres
b. about 10 metres
c. about 1 metre
d. smaller than the width of your hand
ANSWER: d
12. Earth has a radius of about 6400 km, the Sun has a radius of about 7.0×105 km, and a rubber
ball has a radius of 6.4 cm. If you were to construct a scale model of the Solar System using the
rubber ball to represent Earth, what is the radius of a ball needed to represent the Sun in your
model?
a. 7.0 × 105 cm b. 7.0 cm
c. 700 cm
d. 70 cm
ANSWER: c
13. How is a planet different from a star?
a. Planets are larger than stars.
b. Planets reflect light, while stars produce their own light. c. Stars move faster in the sky than
planets.
d. Planets are brighter than stars.
ANSWER: b
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
14. Which of the following is the smallest? a. size of a typical planet
b. 1 AU
c. 1 light-year
d. size of a typical galaxy
ANSWER: a
15. Assume the size of the Sun is represented by a baseball (diameter about 7 cm). At this scale, the
Earth is about 15 metres (150 million km or 8 light-minutes) away. How far away, to scale, would
the nearest stars to the Sun be? Pick the closest answer.
a. about the distance between Windsor and Toronto (about 400 km)
b. about 100 metres away
c. about the distance across Canada from Toronto to Vancouver (about 4300 km) d. about the
distance across 50 football fields (50 x 100 m, or 5 km)
ANSWER: c
16. In the diagram, what is the diameter of Jupiter?
a. about 7.0 × 104 km b. about 7.0 × 105 km c. about 1.4 × 104 km d. about 1.4 × 105 km
ANSWER: d
17. What is 5.7×107 the same as? a. 5.7 million
b. 57 thousand c. 570 thousand d. 57 million
ANSWER: d
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
18. What is 1.95 billion the same as? a. 1.95 × 1012
b. 1.95 × 109 c. 1.95 × 106 d. 1.95 × 105
ANSWER: b
19. How many centimetres are there in one kilometre? a. 100
b. 1,000
c. 10,000 d. 100,000
ANSWER: d
20. What is one thousandth of one metre? a. one kilometre
b. one centimetre
c. one millimetre
d. one hectometre
ANSWER: c
21. Which of the following has the distances arranged in order from smallest to largest? a.
kilometre, light year, millimetre, Astronomical Unit
b. Astronomical Unit, millimetre, light year, kilometre
c. millimetre, kilometre, Astronomical Unit, light year
d. light year, kilometre, Astronomical Unit, millimetre
ANSWER: c
22. Which of the following has the distances arranged in order from largest to smallest? a.
light year, Astronomical Unit, kilometre, millimetre
b. Astronomical Unit, millimetre, light year, kilometre
c. kilometre, millimetre, Astronomical Unit, light year
d. light year, kilometre, Astronomical Unit, millimetre ANSWER: a
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
23. It takes light 1.3 seconds to travel from the Moon to Earth and 8 minutes for light to travel from
the Sun to Earth. Which of the following statements is true?
a. The Sun is 6.2 times farther from Earth than the Moon.
b. The Sun is 10 times farther from Earth than the Moon.
c. The Sun is 370 times farther from Earth than the Moon. d. The Sun is 0.10 times farther from
Earth than the Moon.
ANSWER: c
24. If light takes 8 minutes to travel from the Sun to Earth, and over 4 hours to travel from the Sun
to the planet Neptune, what is the distance from the Sun to Neptune?
a. 5 AU
b. 30 AU
c. 30 ly d. 5 ly
ANSWER: b
25. How long does it take for light to travel from the Sun to Neptune? a. several seconds
b. several minutes
c. several hours
d. several weeks ANSWER: c
26. The speed of light is 3.0×105 km/s, and it takes 1.3 seconds for light to travel from the Moon to
Earth. Based on this information, what is the distance from the Earth to the Moon?
a. 390,000 km
b. 230,000 km
c. 3.9 km d. 2.3 km
ANSWER: a
27. Which sequence is correct when ordered by increasing size? a. Earth, Solar System, Milky Way
Galaxy, clusters of galaxies b. Solar System, Earth, galaxy clusters, Milky Way Galaxy
c. Earth, Milky Way Galaxy, Solar System, galaxy clusters
d. galaxy clusters, Solar System, Milky Way Galaxy, Earth ANSWER: a
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
28. How does one light-year relate to Astronomical Units, roughly? a. 63,000 AU
b. 10,000 AU c. 380,000 AU d. 1,400 AU
ANSWER: a
29. What does a typical galaxy like our Milky Way galaxy contain? a. primarily planets
b. gas only
c. stars (some with planets), gas, and dust
d. a single star and planets
ANSWER: c
30. If the distance to a star is 450 light-years, what can we conclude about the star? a. The
star is 450 million AU away.
b. The star’s light takes 450 years to reach us.
c. The star must have formed 450 billion years ago.
d. The star must be very young.
ANSWER: b
31. How long does it take for light to cross the Milky Way galaxy? a. about 8 minutes
b. about 8 years
c. about 80,000 years
d. about 200 million years
ANSWER: c
32. Which statement best describes the Milky Way Galaxy? a. It contains about 100 billion stars.
b. It is about 400 light-years in diameter.
c. It is the largest known object in the universe.
d. It contains numerous clusters and superclusters. ANSWER: a
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
33. What is the name of the hazy band of light that circles our sky, produced by the glow of our
galaxy? a. the Milky Way
b. the Solar System
c. a spiral arm
d. Alpha Centauri
ANSWER: a
34. If we say that an object is 1,000 light-years away, how does that affect how we see it? a. We see
it as it looked 1,000 years ago.
b. We see it as it would appear to our ancestors 1,000 years ago.
c. We see it as it looked 1,000 light-years ago.
d. We see it as it is right now, but it appears 1,000 times dimmer.
ANSWER: a
35. What is the implication if the distance to the nearest star is 4.2 light-years? a. The star is 4.2
million AU away.
b. The light we see left the star 4.2 years ago.
c. The star must be very old.
d. The star must be very young.
ANSWER: b
36. Which statement best describes the Milky Way Galaxy? a. It is a spiral galaxy.
b. It is comprised of several smaller galaxies.
c. It is about 1,000 light-years in diameter.
d. It is type of supercluster.
ANSWER: a
37. What is the reason for compressing the history of the universe into a single year in the cosmic
calendar? a. to compare astronomical timescales with human experience
b. to emphasize how old the universe is
c. to simplify calculations of ages of objects in the universe
d. to express the distances of objects in light-years ANSWER: a
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
38. Using the cosmic calendar, where the Big Bang happened January 1, in what month did the
Milky Way form? a. January
b. March
c. August
d. December
ANSWER: b
39. The name of the average distance from Earth to the Sun is one ____________________.
ANSWER: AstronomicalUnit
40. Light takes about 8 minutes to travel from the Sun to Earth and about 40 minutes to travel from
the Sun to Jupiter. Jupiter is about ____________________ AU from the Sun.
ANSWER: five(5)
41. The number 52,700,000,000 would be written in scientific notation as ____________________.
ANSWER: 5.27×1010
42. A(n) ____________________ is the largest known structure in the universe.
ANSWER: filament
43. A(n) ____________________ is the distance that light would travel in one year.
ANSWER: light-year
44. A cluster of galaxy clusters is called a(n) ________________________.
ANSWER: supercluster
45. I liveentauri is 4.2 ly away. That means that it takes light ________ years to travel from Proxima
Centauri to the Earth.
ANSWER: 4.2
46. The average distance from Earth to the Sun is 1 AU. a. True
b. False
ANSWER: True
47. The nearest star is 1 ly from the Solar System. a. True
b. False ANSWER: False
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
48. A light-year is the distance that light travels in one year. a. True
b. False
ANSWER: True
49. A kilometre contains 1 million metres. a. True
b. False
ANSWER: False
50. The Sun is a star in the Milky Way Galaxy. a. True
b. False
ANSWER: True
51. The metric system is a decimal system. a. True
b. False ANSWER: True
52.3.49×107 kmisthesameas3.49×104 m. a. True
b. False ANSWER: False
53. The numbers 9.85 × 105 and 985,000 are equivalent. a. True
b. False
ANSWER: True
54. An astronomical unit is larger than a light-year. a. True
b. False
ANSWER: False
55. The Sun is located at the centre of the Milky Way. a. True
b. False ANSWER: False
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Name: Class: Date: CHAPTER 1 - THE SCALE OF THE COSMOS: SPACE AND TIME
56. A supercluster refers to a large group of stars within the Milky Way. a. True
b. False
ANSWER: False
57. Explain the difference between a light-year and the orbital period of Earth.
ANSWER: Answernotprovided. 58. What is scientific notation? Explain.
ANSWER: Answernotprovided.
59. Why would the English system of units be more useful if a foot contained 10 inches?
ANSWER: Answernotprovided.
60. Why do we measure some distances in astronomy in light-years and some in astronomical
units?
ANSWER: Answernotprovided.
61. From what you know about astronomical units and light-years, how would you define a lightminute?
ANSWER: Answernotprovided.
62. “I live 20 minutes from Centre City.” How is this statement similar to giving astronomical
distances in light-years?
ANSWER: Answernotprovided.
63. Describe the difference between a solar system and a galaxy.
ANSWER: Answernotprovided.
64. Considering that the Sun is about 1/100 AU in diameter and a typical planet like Earth is
1/10,000 AU, discuss whether or not our Solar System is crowded or empty.
ANSWER: Answernotprovided.
65. Briefly describe the scientific method. ANSWER: No answer provided.
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
1. Which of the following definitions best describes a constellation? a. a region of the sky
containing a certain star pattern
b. a group of very bright stars
c. a group of very faint stars
d. the dividing line between the north and south celestial hemispheres
ANSWER: a
2. How many official constellations are there? a. 98
b. 88 c. 13 d. 55
ANSWER: b
3. Which of the following best describes the Big Dipper? a. an asterism
b. a faint star near Polaris
c. the North Star
d. a constellation
ANSWER: a
4. What do stars in the same constellation have in common?
a. They probably formed at the same time.
b. They must be part of the same cluster of stars in space.
c. They must have been discovered at about the same time.
d. They are in the same part of the sky as seen from the Earth.
ANSWER: d
5. Which of the following best describes Ursa Major (the Great Bear)? a. a constellation
b. another name for the Seven Sisters
c. an asterism
d. another name for the Big Dipper ANSWER: a
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6. What languages do the standard constellation names come from? a. Greek and Latin
b. Latin and Arabic
c. Greek and Arabic
d. Arabic and Sanskrit
ANSWER: a
7. Which of the following statements correctly describes the relationship between stars and
constellations? a. Only stars close to the ecliptic (the Earth's orbital plane) are located in
constellations.
b. Every star is located in a constellation.
c. Only the brighter stars are in constellations.
d. Only those stars that were visible to the ancient Greeks are located in constellations.
ANSWER: b
8. What language is the source of most star names, such as Aldebaran and Betelgeuse? a.
Latin
b. Greek c. Arabic d. Italian
ANSWER: c
9. If the apparent visual magnitude of a star is 7.3, what does this tell us about the
brightness of the star? a. It is one of the brighter stars in the sky.
b. It is bright enough that it would be visible even during the day.
c. It is not visible with the unaided eye.
d. It appears faint because of its great distance from the Earth.
ANSWER: c
10. The star Vega has an apparent visual magnitude of 0.03 and the star HR 4374 has an
apparent visual magnitude of 4.87. It has been determined that both stars are at the same
distance from the Earth. What does this information tell us about the two stars?
a. Together the two stars would have a magnitude of 4.9.
b. Vega must produce less energy per second than HR 4374. c. Vega must produce more
energy per second than HR 4374. d. Vega will appear fainter to us than HR 4374.
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
11. Which of the following describes the magnitude scale?
a. It originated just after the telescope was invented.
b. It can be used to indicate the apparent intensity of a celestial object. c. It is no longer used
today.
d. It was used to determine the rate of precession.
ANSWER: b
12. What is the apparent visual magnitude of a star a measure of? a. the star’s size as
perceived by human eyes on Earth
b. the star’s temperature as perceived by human eyes on Earth c. the star’s colour as seen by
human eyes on Earth
d. the star’s brightness as seen by human eyes on Earth
ANSWER: d
13. What kind of letters are used to identify stars in a constellation? a. Arabic letters
b. Italic letters
c. Latin letters
d. Greek letters
ANSWER: d
14. If the apparent visual magnitude of star A is 3.1, and the apparent visual magnitude of
star B is 0.5, how do star A and star B compare in terms of apparent brightness as seen
from Earth?
a. Star A is fainter than star B.
b. Star A is much brighter than star B.
c. Star A is about the same brightness as star B. d. Star A is only slightly brighter than star B.
ANSWER: a
15. What is the purpose of the magnitude scale?
a. It measures the apparent location of celestial objects in the sky. b. It measures the
apparent size of a celestial object.
c. It measures the apparent brightness of a celestial object.
d. It measures the apparent speed of a celestial object.
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
Magnitude
Table 2-1
Star Name
δ Dra α Cet Nim
α CMa
Apparent Visual Magnitude
3.07 2.53 8.07
−1.46
16. Refer to Table 2-1. Which star in the table would appear brightest to an observer on
Earth? a. δ Dra
b. α Cet c. Nim
d. α CMa
ANSWER: d
17. Refer to Table 2-1. Which star in the table would be invisible to the unaided eye of an
observer on Earth? a. δ Dra
b. α Cet c. Nim
d. α CMa
ANSWER: c
18. What causes the precession of the Earth’s rotation axis?
a. the force of gravity from the Sun and Moon on the Earth's equatorial bulge b. the force of
gravity from the Sun and Jupiter on the Earth–Moon system
c. the magnetic field of the Earth
d. the impacts of asteroids
ANSWER: a
19. Where is an observer's nadir?
a. the east point on the observer's horizon
b. the north point on the observer's horizon
c. the point directly opposite the observer's zenith d. the point directly opposite the north
celestial pole
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
20. What aspect of an object depends on both the size of the object and the distance to the
object? a. apparent brightness
b. apparent magnitude
c. angular diameter
d. proper motion ANSWER: c
21. Which of the following is equivalent to one-3,600th of a degree? a. precession
b. second of arc
c. minute of arc
d. angular diameter
ANSWER: b
22. What is the term for the point on the celestial sphere directly above an observer, no
matter where on the Earth the observer is located?
a. north celestial pole
b. south celestial pole
c. zenith d. nadir
ANSWER: c
23. Where is the zenith for an observer standing at a point on the Earth’s equator? a.
directly overhead
b. near the horizon and towards the south
c. near the horizon and towards the west
d. the position depends on the time of day
ANSWER: a
24. An observer in the northern hemisphere watches the sky for several hours. Due to the
motion of the Earth, this observer notices that the stars near the north celestial pole appear
to move. What pattern does this apparent movement follow?
a. clockwise around the celestial pole
b. counter-clockwise around the celestial pole c. from left to right
d. from right to left
ANSWER: b
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
25. The Moon has an angular diameter of 0.5°. What is the Moon's angular diameter in
minutes of arc? a. 0.5
b. 30
c. 50
d. 1800
ANSWER: b
26. You point your finger toward the zenith right now, and then point there again six hours
later. At both times, your finger was pointing in the same direction relative to one of the
options below. Which one?
a. your horizon
b. the Sun
c. the Moon
d. the fixed stars
ANSWER: a
27. If an observer travels north, toward higher latitudes, how does the number of
circumpolar stars that he or she sees in the sky change?
a. remains constant
b. decreases
c. increases
d. also depends on the longitude of the observer
ANSWER: c
28. If you were standing at the Earth's North Pole, which of the following would be located
at the zenith? a. the nadir
b. the star Vega
c. the celestial equator
d. the north celestial pole
ANSWER: d
29. How much of the night sky lies north of the celestial equator?
a. Less than half, because of the tilt of the equator to the ecliptic plane. b. More than half,
because of the precession of the poles.
c. Exactly half.
d. All of the night sky.
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
30. If you were standing on the Earth's equator, which of the following in the sky would
pass through your zenith during the entire day (24 hours)?
a. the north celestial pole
b. the south celestial pole
c. the celestial equator
d. circumpolar constellations
ANSWER: c
31. Seen from Winnipeg (latitude 50 degrees North), where is the star Polaris in the sky? a.
directly overhead
b. 40 degrees above the horizon
c. 50 degrees above the horizon
d. the position depends on the time of day
ANSWER: c
32. Seen from Yellowknife (latitude 62 degrees North), where is the star Polaris in the sky?
a. directly overhead
b. 62 degrees above the horizon
c. 28 degrees above the horizon
d. the position depends on the time of day
ANSWER: b
33. For an observer in Pond Inlet, Nunavut, at a latitude of 73° North, what is the angle
between the northern horizon and the north celestial pole?
a. 17°
b. 23.5°
c. 27° d. 73°
ANSWER: d
34. For an observer in Valdivia, Chile, at a latitude of 39° South, what is the angle between
the southern horizon and the south celestial pole?
a. 23.5°
b. 45°
c. 39° d. 51°
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
35. For an observer in New Delhi, India, at a latitude of 28° North, what is the angle
between the northern horizon and the north celestial pole?
a. 5°
b. 28°
c. 40° d. 62°
ANSWER: b
36. For an observer in Lusaka, Zambia, at a latitude of 16° South, what is the angle between
the southern horizon and the south celestial pole?
a. 16°
b. 23.5°
c. 74° d. 164°
ANSWER: a
37. For an observer in Toronto, at a latitude of 44° North, what is the angle between the
northern horizon and the north celestial pole?
a. 23.5°
b. 36°
c. 44° d. 74°
ANSWER: c
38. For an observer in Oberon Bay, Australia, at a latitude of 39° South, what is the angle
between the southern horizon and the south celestial pole?
a. 23.5°
b. 39°
c. 45° d. 51°
ANSWER: b
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
39. If the north celestial pole appears on your horizon, what is your latitude? a. 0°
b. 45° N c. 90° N d. 90° S
ANSWER: a
40. What is the approximate latitude of the observer in the diagram?
a. 50° N b. 50° S c. 90° N d. 90° S
ANSWER: a
41. What is the approximate latitude of the observer in the diagram?
a. 20° N b. 20° S c. 70° N d. 0°
ANSWER: b
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
42. An observer in the northern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due north
b. due south
c. due east
d. straight up, directly overhead
ANSWER: b
43. An observer in the northern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due north
b. due south
c. due west
d. straight up, directly overhead
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
44. An observer in the southern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due south
b. due east
c. due west
d. straight up, directly overhead
ANSWER: a
45. An observer in the southern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due north b. due south c. due east d. due west
ANSWER: c
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
46. An observer in the northern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due north
b. due south
c. due west
d. straight up, directly overhead
ANSWER: a
47. An observer in the southern hemisphere takes a time exposure photograph of the night
sky. If the illustration depicts the photograph taken by the observer, which direction was
the camera pointing?
a. due north b. due south c. due east d. due west
ANSWER: d
48. Where in the sky would an observer at the Earth's equator see the celestial equator? a.
The celestial equator would be at 45 degrees above the northern horizon.
b. The celestial equator would be at 45 degrees above the southern horizon.
c. The celestial equator would coincide with the horizon.
d. The celestial equator would be directly overhead. ANSWER: d
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
49. What is the celestial equator?
a. the dividing line between the north and south celestial hemispheres
b. a line around the sky directly above the Earth's poles
c. the path that the Sun appears to follow on the celestial sphere as the Earth orbits the Sun
d. the path that the planets appear to follow in the sky
ANSWER: a
50. How far, and in what direction, does the Sun appear to move on the celestial sphere per
day? a. about one degree westward
b. about one degree eastward
c. about 360 degrees westward
d. about 360 degrees eastward
ANSWER: b
51. Which of the following best defines the ecliptic?
a. the plane that is perpendicular to the Earth's axis of rotation
b. the projection of the Earth's equator onto the sky
c. the path traced out by the Moon in our sky in one month against the background stars d.
the path traced out by the Sun in our sky over one year against the background stars
ANSWER: d
52. What is the ecliptic?
a. the centre line of the celestial sphere
b. the projection of the Earth's orbit on the sky
c. the apparent path of the Moon around the sky
d. the line between east and west, passing through the zenith
ANSWER: b
53. Which planet(s) in our solar system is (are) never visible to the naked eye? a. Mercury
and Neptune
b. Saturn, Uranus, and Neptune
c. Neptune
d. Mercury and Venus ANSWER: c
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54. If you see the Sun pass directly overhead on at least one day per year, then where are
you on Earth? a. within 23.5° latitude of the equator
b. within 66.5° latitude of the equator
c. exactly on the equator
d. could be anywhere, because this occurs at least once per year at any location on the Earth
ANSWER: a
55. Through the year, the Sun moves eastward among the stars following a line called the a.
equator
b. horizon c. ecliptic d. zenith
ANSWER: c
56. In Brazil, in what month does the longest period of daylight occur? a. March
b. June
c. September d. December
ANSWER: d
57. Around what date is the amount of solar energy per square metre that is incident upon
the surface of the Earth in the northern hemisphere at its lowest level?
a. December 21, the winter solstice
b. March 21, the vernal equinox
c. June 21, the summer solstice
d. September 21, the autumnal equinox
ANSWER: a
58. If the Earth's rotational axis shifted to a position perpendicular to the ecliptic, what
would happen to seasonal variations on the Earth?
a. They would be non-existent.
b. They would remain the same as they are now.
c. They would have the same severity but each season would last twice as long. d. They
would be much more severe.
ANSWER: a
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59. If the perihelion of the Earth was significantly closer to the Sun than is currently the
case, what would be the probable effect on the climate of the Southern Hemisphere?
a. The winter season would be much colder than at present.
b. The winter season would be much warmer than at present.
c. The summer season would be much colder than at present. d. The summer season would
be much warmer than at present.
ANSWER: d
60. What is the term for the point in the Earth's orbit where the Earth is farthest from the
Sun? a. aphelion
b. perihelion
c. precession
d. the winter solstice
ANSWER: a
61. What is the term for the point in the Earth's orbit where the Earth is closest to the Sun?
a. aphelion
b. perihelion
c. precession
d. the vernal equinox
ANSWER: b
62. On the vernal equinox (March 21), where is the Sun on the celestial sphere? a. 23.5°
north of the celestial equator
b. 23.5° south of the celestial equator
c. on the celestial equator and moving north with respect to the equator
d. on the celestial equator and moving south with respect to the equator
ANSWER: c
63. On the autumnal equinox (Sept. 21), where is the Sun on the celestial sphere? a. 23.5°
north of the celestial equator
b. 23.5° south of the celestial equator
c. on the celestial equator and moving north with respect to the equator
d. on the celestial equator and moving south with respect to the equator ANSWER: d
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64. At which of the following times would you find the Sun on the celestial equator? a.
vernal equinox and summer solstice
b. autumnal equinox and vernal equinox
c. summer solstice and winter solstice
d. autumnal equinox and winter solstice
ANSWER: b
65. At what two celestial locations do the celestial equator and the ecliptic coincide? a.
winter solstice and summer solstice
b. vernal equinox and autumnal equinox
c. north celestial pole and south celestial pole
d. zenith and east point ANSWER: b
Horizon 1
66. The diagram shows three approximate locations of the Sun along the western horizon.
Which number indicates the location of the Sun at sunset on December 21st (winter
solstice) for an observer at latitude 48° North?
a. 1
b. 2
c. 3
d. The Sun will not set on December 21st at this latitude.
ANSWER: a
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Horizon 2
67. The diagram shows three approximate locations of the Sun along the western horizon.
Which number indicates the location of the Sun at sunset on autumnal equinox (Sept. 21)
for an observer at a latitude of 45° North?
a. 1
b. 2
c. 3
d. The Sun will not set on the autumnal equinox at this latitude.
ANSWER: b Horizon 3
68. The diagram shows three approximate locations of the Sun along the western horizon.
Which number indicates the location of the Sun at sunset on the vernal equinox (March 21)
for an observer at a latitude of 48° South?
a. 1
b. 2
c. 3
d. The Sun will not set on the vernal equinox at this latitude.
ANSWER: b Horizon 4
69. The diagram shows three approximate locations of the Sun along the western horizon.
Which number indicates the location of the Sun at sunset on June 21 (summer solstice) for
an observer at a latitude of 37° North?
a. 1
b. 2
c. 3
d. The Sun will not set on June 21 at this latitude.
ANSWER: c
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Horizon 5
70. The diagram shows three approximate locations of the Sun along the western horizon.
Which number indicates the location of the Sun at sunset on June 21 (summer solstice) for
an observer at a latitude of 77° North?
a. 1
b. 2
c. 3
d. The Sun will not set on June 21 at this latitude.
ANSWER: d
71. Why are Northern Hemisphere winters colder than Northern Hemisphere summers?
a. The Earth is closer to the Sun during the summer than it is during the winter.
b. The snow that falls in the northern latitudes cools the Earth during the winter.
c. The light from the Sun shines more directly on the Northern Hemisphere during the
summer. d. The period of sunlight is shorter during the summer than during the winter.
ANSWER: c
72. What is the angle between the noon Sun at the winter solstice and the southern horizon
for an observer at a latitude of 38° North?
a. 28.5°
b. 38°
c. 52° d. 75.5°
ANSWER: c
73. What is the term for a set of beliefs that appears to be based on scientific ideas, but
which fails to obey the most basic rules of science?
a. theory
b. hypothesis
c. pseudoscience d. scientific model
ANSWER: c
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74. Why are Venus and Mercury often called “morning star” and “evening star”? a. They look
more like stars than the other planets do.
b. They both rotate quite slowly and have long mornings and evenings.
c. They are both reddish in colour, like the Sun near the horizon.
d. They are only visible just before sunrise or just after sunset.
ANSWER: d
75. What determines the phase of the Moon on a particular night? a. the speed of the Moon
in its orbit
b. the relative positions of the Sun, the Earth, and the Moon c. how the Earth’s shadow hits
the moon
d. the distance from the Earth to the Moon
ANSWER: b
76. If you lived on the near side of the Moon, how often would the Earth set below your
horizon? a. every 24 hours
b. once a sidereal period (27.3 days)
c. once a synodic period (29.5 days)
d. never
ANSWER: d
77. On a clear night, when an observer in Vancouver sees a first quarter Moon, what would
an observer in St. John’s see?
a. a new Moon
b. a first quarter Moon c. a third quarter Moon d. a full Moon
ANSWER: b
78. When does the first quarter Moon rise? a. at about noon
b. at sunset
c. at sunrise
d. at about midnight ANSWER: a
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79. Relative to the stars, the Moon moves eastward in the sky each night. About how far
does it move? a. 1°
b. 13° c. 27.3° d. 29.5°
ANSWER: b
80. What is the term for the Moon when it is visible above the western horizon a couple of
hours before sunrise? a. the waning gibbous Moon
b. the waxing gibbous Moon
c. the waxing crescent Moon
d. the waning crescent Moon
ANSWER: a
81. What is the term for the Moon when it is visible above the eastern horizon a couple of
hours before sunrise? a. the waning gibbous Moon
b. the waxing gibbous Moon
c. the waxing crescent Moon
d. the waning crescent Moon
ANSWER: d
82. When and where is a waxing crescent Moon visible? a. near the eastern horizon just
before sunrise
b. near the eastern horizon just after sunset
c. near the western horizon just before sunrise
d. near the western horizon just after sunset
ANSWER: d
83. When and where is a third quarter Moon visible? a. near the eastern horizon just after
sunset
b. in the southern sky at sunrise
c. in the southern sky at sunset
d. from sunset until sunrise ANSWER: b
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84. If someone on Earth observes the Moon in the third quarter phase, what phase would
someone on the Moon facing Earth observe Earth in?
a. the full Earth phase
b. the third quarter Earth phase
c. the first quarter Earth phase d. the new Earth phase
ANSWER: c
85. If the Moon is setting at 6 a.m., what phase must the Moon be in? a. full
b. new
c. third quarter d. first quarter
ANSWER: a
86. When and where is a first quarter Moon visible? a. near the eastern horizon just after
sunset
b. in the southern sky at sunrise
c. in the southern sky at sunset
d. from sunset until sunrise
ANSWER: c
87. If the Moon is setting at noon, what phase must the Moon be in? a. first quarter
b. new
c. third quarter
d. waxing crescent
ANSWER: c
88. When does the full Moon occur?
a. on the 15th of every month
b. when the Moon is at right angles to the direction of the Sun c. when the Moon is closer to
Sun than the Earth is
d. when the Moon is directly opposite the position of the Sun
ANSWER: d
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89. In which direction does the daily motion of the Moon occur in the sky, against the
background stars, when viewed from the Earth?
a. toward the west
b. toward the east
c. toward the north celestial pole in the summer and the south celestial pole in the winter d.
No predictable pattern can be discerned.
ANSWER: b
90. What is the term for a solar eclipse in which the Moon's umbra reaches the Earth's
surface? a. a total solar eclipse
b. a partial solar eclipse
c. a penumbral solar eclipse
d. an umbral solar eclipse
ANSWER: a
91. When does a solar or lunar eclipse occur?
a. when the Sun is near the plane of the Moon’s orbit, and the Moon is new or full b. any
time the Moon is new or full
c. halfway through an eclipse year
d. when the Sun is near the equinox and the Moon is new or full
ANSWER: a
92. What is the term for a solar eclipse in which the Moon's umbra does not reach the
Earth's surface? a. a partial solar eclipse
b. an annular solar eclipse
c. a penumbral solar eclipse
d. an umbral solar eclipse
ANSWER: b
93. What is the term for a lunar eclipse in which the Moon moves completely into the
Earth’s umbral shadow? a. a partial lunar eclipse
b. an annular eclipse
c. a penumbral lunar eclipse
d. a total lunar eclipse ANSWER: d
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94. How does the Moon’s appearance change during a total lunar eclipse? a. The Moon goes
from new to full.
b. The Moon disappears.
c. The Moon turns a dark red colour.
d. The Moon’s far side is visible.
ANSWER: c
95. Which of the following is 18 years and 11-1/3 days long? a. sidereal period
b. synodic period
c. eclipse season
d. Saros cycle
ANSWER: d
96. What is the Saros cycle?
a. the pattern of repetition of solar and lunar eclipses
b. the time between annular eclipses at a particular location c. the number of full Moons in a
year
d. the pattern of events that happen in a single eclipse
ANSWER: a
97. Why does a totally eclipsed Moon glow coppery red?
a. Only red light can pass through the Earth’s shadow and reach the Moon.
b. During a lunar eclipse the Moon reflects only red light from the Sun.
c. During a lunar eclipse the Sun is cooler than normal, so its light is redder.
d. Only red light is able to pass completely through the Earth's atmosphere and reach the
Moon.
ANSWER: d
98. The Moon’s umbral shadow usually does not produce a total solar eclipse. Why not? a.
shadow is too bright
b. shadow is too faint
c. shadow is too long
d. shadow is too short ANSWER: d
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99. Where is a total lunar eclipse visible?
a. It is visible only from the path of totality.
b. It is visible only to observers who can see the new Moon.
c. It is visible to all observers on the side of the Earth facing the Moon. d. It is visible only
from the Earth’s equator.
ANSWER: c
100. When do total lunar eclipses always occur? a. at the time of new Moon
b. at the time of full Moon
c. during either equinox
d. during either solstice
ANSWER: b
101. If the Moon’s orbital plane was aligned with the celestial equator, when would eclipses
occur? a. every month
b. never
c. only at solstices
d. only at the equinoxes
ANSWER: d
102. Why doesn’t the Earth experience a solar eclipse every month? a. Unpredictable
weather patterns obscure the Moon.
b. The Moon always keeps its same side toward the Earth.
c. The Moon’s orbit is not aligned with the Earth’s orbit.
d. Sometimes the Moon is too far away.
ANSWER: c
103. A total solar eclipse occurred in Brandon, Manitoba, on Feb. 26, 1979. At what other
date was there (or will there be) the same eclipse visible at this location?
a. March of 1979
b. August of 1979
c. January of 2000 d. March of 2033
ANSWER: d
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104. During a total lunar eclipse, where is the Moon? a. in the solar umbra
b. in the Earth’s umbra
c. between the Earth and the Sun
d. at its greatest distance from the Earth
ANSWER: b
105. Which of the following describes a concept very similar to latitude? a. right ascension
b. declination c. magnitude d. meridian
ANSWER: b
106. For an observer at the North Pole, what is the angular distance between a star at a
declination of +30° and the zenith?
a. 30° b. 60° c. 90° d. 150°
ANSWER: b
107. The star delta Cephei has a declination of about +58.5 degrees. Which observer will see
it above their horizon for the longest fraction of one night?
a. an observer in Valdivia, Chile, at a latitude of 39° S
b. an observer in Windhoek, Namibia, at a latitude of 22.5° S
c. an observer in Zacatecas, Mexico, at a latitude of 22.5° N d. an observer in Edmonton,
Canada, at a latitude of 53.5° N
ANSWER: d
108. The second is defined as a fixed interval of time, with no reference to astronomical
timescales. If the Earth's period of rotation doubled, but its period of revolution stayed the
same, what would happen?
a. There would half as many seconds in the day.
b. There would be twice as many seconds in the day.
c. There would be half as many seconds in the year. d. There would be twice as many
seconds in the year.
ANSWER: b
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109. Which of the following measures time relative to the stars? a. solar day
b. sidereal day
c. tropical year d. synodic month
ANSWER: b
110. You want to observe the star Arcturus just as it crosses the meridian. If the meridian
crossing happens at exactly 9:00 p.m. tonight, at what time will it occur 7 days from now, at
the same location?
a. 8:32 p.m.
b. 9:00 p.m.
c. 9:28 p.m. d. 6:00 a.m.
ANSWER: a
111. Do the constellations visible in the sky at a particular time of night (say 9 p.m.) follow a
seasonal pattern?
1. No, the same constellations are visible at 9 p.m. on any clear night of the year.
2. No. As the year progresses, the constellations visible at 9 p.m. are the same, but their
shapes change.
3. Yes, at 9 p.m. on a clear winter night, ALL of the constellations you can see are
different from the ones that appear at the same time on a summer night.
4. Yes, at 9 p.m. on a summer night, MOST of the constellations you can see are
different from those you can see on a winter night. Some constellations are visible
all year long.
ANSWER: d
112. Why does the Gregorian calendar use leap years?
a. because the tropical year is 365 days, 5 hours, and 49 minutes long b. because the
sidereal year is 365 days, 6 hours, and 9 minutes long c. because the Earth’s axis is
precessing
d. because the Earth’s rotation is slowing down
ANSWER: b
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113. What is the term for the period of time it takes for the Moon to complete a cycle of the
lunar phases that is approximately 29.5 days long?
a. sidereal period of the Moon
b. Saros cycle of the Moon
c. synodic period of the Moon d. eclipse season of the Moon
ANSWER: c
114. What is the sidereal period of the Moon?
a. the period of time between one full Moon and the next
b. the period of time for the Moon to orbit the Earth once with respect to the stars
c. the period of time between successive eclipses at a given location on Earth
d. the period of time from when the Moon rises until the Moon rises again the next night
ANSWER: b
115. What is apparent solar time?
a. the time between successive meridian crossings of a particular star
b. time measured relative to successive meridian crossings of the Sun
c. the period of time between successive solar eclipses at a given location on Earth d. time
measured relative to sunrise and sunset
ANSWER: b
116. During the month of June, the north celestial pole points towards Polaris; where does it
point during the month of December?
a. just south of Polaris
b. towards the star Vega
c. towards the star Thuban d. still towards Polaris
ANSWER: d
117. Which of the following is a prominent constellation in the Canadian winter sky? a.
Taurus
b. Aquila c. Cygnus d. Virgo
ANSWER: a
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118. In what season is the constellation of Orion most visible in Canada? a. spring
b. summer c. fall
d. winter
ANSWER: d
119. Which of the following constellations is visible year-round in most of Canada? a.
Gemini
b. Libra
c. Orion
d. Cassiopeia
ANSWER: d
120. Why is the constellation Leo not visible all year from Canada?
a. Leo is in the southern celestial hemisphere.
b. Leo is on the ecliptic, so it is sometimes directly behind the Sun in the sky.
c. Leo is on the celestial equator, so it is often directly behind the Moon in the sky. d. Leo has
no stars visible to the unaided eye.
ANSWER: b
121. In what two seasons does the Milky Way arc from east to west in the sky, as seen from
Canada? a. winter and spring
b. spring and summer c. summer and fall
d. fall and winter
ANSWER: d
122. ____________________ is a measure of the light energy that hits one square metre in one
second.
ANSWER: Flux
123. Star A has an apparent visual magnitude of 6.3 and star B has an apparent visual
magnitude of 5.3. Star A is ____________________ than star B.
ANSWER: fainter
124. The ____________________ is the point on the celestial sphere directly above an observer,
regardless of where the observer is located on Earth.
ANSWER: Zenith
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125. The full Moon has an angular diameter of approximately ____________________ arc minutes
for an observer located on the surface of the Earth.
ANSWER: 30(thirty)
126. The Earth's rotation axis ____________________ slowly so that in a few thousand years
Polaris will no longer be the North Star.
ANSWER: precesses
127. ______________ is the point in the Earth's orbit when the Earth is closest to the Sun.
ANSWER: Perihelion
128. The planets ____________ and _____________ are never visible near the eastern horizon at
sunset.
ANSWER: Mercury,VenusORVenus,Mercury
129. For a northern hemisphere observer, the _____________ ____________ Moon is visible in the
south-eastern sky just after sunset.
ANSWER: waxinggibbous
130. A(n) ____________________ eclipse occurs when the Moon is at its greatest distance from
the Earth, and the Moon is new.
ANSWER: annular
131. The ____________________ period of the Moon is the time required for one revolution of the
Moon around the Earth with respect to the stars.
ANSWER: sidereal
132. The constellations were created by the Greeks. a. True
b. False
ANSWER: False
133. A second magnitude star in Ursa Major is brighter than a fourth magnitude star in
Orion. a. True
b. False ANSWER: True
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134. The Greek letter designation conveys information about a star's location and
brightness. a. True
b. False
ANSWER: True
135. The celestial equator always passes directly overhead. a. True
b. False
ANSWER: False
136. The celestial equator always crosses the horizon at the east point and west point. a.
True
b. False
ANSWER: True
137. Navigators can find their latitude in the northern hemisphere by measuring the angle
from the northern horizon to the north celestial pole.
a. True
b. False
ANSWER: True
138. A scientific model is a mental conception that provides a framework that helps us think
about some aspect of nature.
a. True b. False
ANSWER: True
139. The constellation of Orion is currently visible in the evenings in January. Precession
will not affect this, and 13,000 years from now Orion will still be visible in January.
a. True
b. False
ANSWER: False
140. A third magnitude star is three times brighter than a first magnitude star. a. True
b. False ANSWER: False
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141. As the Earth rotates, circumpolar stars appear to move counterclockwise around the
north celestial pole. a. True
b. False
ANSWER: True
142. The third quarter Moon rises at noon. a. True
b. False
ANSWER: False
143. During an annular eclipse of the Sun, the corona of the Sun is visible. a. True
b. False
ANSWER: False
144. A total solar eclipse will be visible from the same location on Earth one Saros cycle
later. a. True
b. False
ANSWER: False
145. The path of totality for a solar eclipse is swept out by the tip of the Moon's umbra as
the umbra moves over the Earth.
a. True b. False
ANSWER: True
146. A total lunar eclipse is visible only from the path of totality. a. True
b. False
ANSWER: False
147. If you were on the Moon during a total lunar eclipse, the Sun would be hidden behind
the Earth. a. True
b. False ANSWER: True
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148. The totally eclipsed Moon glows coppery red because sunlight reaches the Moon's
surface after passing through the Earth's atmosphere.
a. True
b. False
ANSWER: True
149. An eclipse season is the interval during which the Sun crosses a node of the Moon's
orbit. a. True
b. False
ANSWER: True
150. The umbra of the Moon's shadow is the region from which no part of the photosphere
is visible. a. True
b. False
ANSWER: True
151. The Moon and visible planets are always within a few degrees of the ecliptic. a. True
b. False
ANSWER: True
152. Precession of the Earth's axis causes the date at which perihelion of the Earth's orbit
occurs to slowly change. a. True
b. False
ANSWER: True
153. Polaris has always been the star nearest the north celestial pole. a. True
b. False
ANSWER: False
154. The seasons are caused by the precession of the Earth's axis. a. True
b. False ANSWER: False
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155. A lunar eclipse can only occur during the full phase of the Moon, i.e. when the Moon is
full. a. True
b. False
ANSWER: True
156. Describe the path that a star on the celestial equator follows from the time it rises until
it sets, a) for a person at a latitude of 60° North, and b) for a person at the equator.
ANSWER: Answernotprovided.
157. Describe the location of Polaris in the sky relative to the horizon as seen by observers
in Yukon (lat. = 60° N), Texas (lat. = 33° N), Ecuador (lat. = 0°), and Australia (lat. = 30° S)
ANSWER: Answernotprovided.
158. What information does a star's Greek-letter designation convey?
ANSWER: Answernotprovided.
159. What advantage is there in referring to a star by its Greek-letter designation and
constellation name rather using its traditional name?
ANSWER: Answernotprovided.
160. How are the celestial poles and equator defined by the Earth's rotation?
ANSWER: Answernotprovided.
161. How is a constellation different from an asterism?
ANSWER: Answernotprovided.
162. Why does the Moon glow coppery red during a total lunar eclipse?
ANSWER: Answernotprovided.
163. Why have more people seen total lunar eclipses than total solar eclipses?
ANSWER: Answernotprovided.
164. Why don't eclipses occur at every new Moon and full Moon?
ANSWER: Answernotprovided.
165. What would you see if you were on the Moon and facing the Earth when people on the
Earth saw a total lunar eclipse?
ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 2 - USER'S GUIDE TO THE SKY: PATTERNS AND CYCLES
166. Why does one cycle of lunar phases take 29.53 days, even though the Moon orbits the
Earth in 27.32 days? ANSWER: Answernotprovided.
167. How do tidal forces affect the rotation of celestial bodies and their orbital motion?
ANSWER: Answernotprovided.
168. Why are penumbral eclipses less obvious than partial eclipses? ANSWER:
Answernotprovided.
169. Describe how a small change in the relative distance of the Earth from the Sun at
perihelion could affect the formation of glaciers on Earth.
ANSWER: Answernotprovided.
170. Why isn't the winter solstice the coldest day of the year?
ANSWER: Answernotprovided.
171. Give two reasons why summer days are warmer than winter days.
ANSWER: Answernotprovided.
172. Why can neither Venus nor Mercury remain visible throughout the night as the full
Moon does?
ANSWER: Answernotprovided.
173. What causes precession, and why does it move the celestial equator?
ANSWER: Answernotprovided.
174. Explain why people who live close to the equator do not experience major temperature
changes in the seasons.
ANSWER: Answernotprovided.
175. The Earth is closest to the Sun during the month of January. Yet we do not experience
our hottest weather in January. Explain why not.
ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 3 - THE ORIGIN OF MODERN ASTRONOMY
1. In 1054 CE, the Chinese recorded a very interesting and powerful cosmic event. What
was this event? a. a star merger
b. a supernova
c. a galactic collapse
d. simultaneous solar and lunar eclipses
ANSWER: b
2. What was a common feature of astronomy as practiced worldwide prior to the Greeks? a.
recognizing patterns
b. making hypotheses
c. defining the 24-hour clock
d. observing supernovae
ANSWER: a
3. What did Eratosthenes measure very accurately? a. the size of the Earth
b. the length of the year
c. the distance to the Moon
d. the length of the month
ANSWER: a
4. Who were the two great authorities of Greek astronomy? a. Aristotle and Ptolemy
b. Julius Caesar and Aristotle
c. Columbus and Ptolemy
d. Alexander the Great and Julius Caesar
ANSWER: a
5. Whose writings became so famous that he was known throughout the Middle East simply
as “The Philosopher”? a. Ptolemy
b. Eratosthenes c. Aristotle
d. Hipparchus
ANSWER: c
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6. Which of the following statements reflects beliefs that were almost universally held in
pre-Copernican astronomy? a. The planets travelled in elliptical orbits around the Earth.
b. The planets travelled in elliptical orbits around the Sun.
c. The Sun was at the centre of the universe.
d. The Earth was at the centre of the universe.
ANSWER: d
7. In what circumstances is retrograde motion observable?
a. It is observable for planets located between the Earth and the Sun. b. It is observable for
planets more distant from the Sun than the Earth c. It is only observable for the Moon.
d. It is observable for all planets.
ANSWER: b
8. You are observing the night sky from Mars. In what circumstances is retrograde motion
observable? a. It is observable for planets more distant from the Sun than Mars.
b. It is observable for planets located between Mars and the Sun.
c. It is only observable for Earth and Venus.
d. It is observable for all planets.
ANSWER: a
9. What is the term for the apparent westward motion of a planet in the sky compared to
the background stars (as viewed from the Earth) when observed on successive nights?
a. epicycle
b. retrograde motion
c. prograde motion d. heliocentric motion
ANSWER: b
10. What is parallax?
a. the apparent motion of an object due to the motion of the observer
b. the distance between two straight lines
c. the small circle that the planets slid along in Ptolemy’s geocentric universe d. the distance
between two foci of an ellipse
ANSWER: a
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11. What was the reason for using epicycles and deferents to explain the motion of the
planets in the night sky? a. prograde motion
b. Mercury and Venus’s limited angular distance from the Sun
c. retrograde motion
d. non-uniform speed of the planets in their orbits
ANSWER: c
12. Why did ancient astronomers believe that the Earth did not move? a. because they could
not detect parallax
b. because they believed in circular motion
c. because all observable planets follow retrograde motion
d. because parallax is only detectable during the day
ANSWER: a
13. In Ptolemy’s view of the universe, what is at the centre of a planet’s epicycle? a. the Sun
b. the Earth
c. the deferent d. the equant
ANSWER: c
14. What is the term for a small circle that has its centre located on the circumference of
another larger circle? a. equant
b. deferent
c. retrograde loop d. epicycle
ANSWER: d
15. What feature of Ptolemy’s model of the universe made it possible to explain retrograde
motion? a. heliocentrism
b. elliptical orbits
c. epicycles
d. geocentrism ANSWER: c
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16. Which of the following astronomers described the universe in a way that matches the
diagram?
a. Kepler
b. Ptolemy
c. Copernicus d. Galileo
ANSWER: b
17. The Copernican system was no more accurate than the Ptolemaic system in predicting
the positions of the planets because of a key factor that was unchanged from the Ptolemaic
system. What was that factor?
a. The Copernican system assumed the Earth was at rest at the centre.
b. The Copernican system used elliptical planetary orbits.
c. The Copernican system used uniform circular motion.
d. The Copernican system assumed all planets orbited the Sun.
ANSWER: c
18. What is the book “De Revolutionibus Orbium Coelestium” about?
a. It describes how Galileo’s observations and Kepler’s calculations proved the Copernican
theory. b. It describes the construction of Galileo’s telescope and his observations.
c. It is a dialogue written to convince the general public of the merits of the Copernican
theory.
d. It lays out the Copernican theory for the first time.
ANSWER: d
19. What was the greatest inaccuracy in Copernicus’s model of the solar system?
a. that the planets travelled in circular orbits with uniform motion
b. that the planets travelled on epicycles, the centres of which followed orbits around the
Sun c. that the planets travelled in elliptical orbits
d. that the planets were allowed to travel backwards in their orbits
ANSWER: a
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20. Which of the following objects cannot transit (i.e. pass in front of) the Sun, as seen from
Jupiter? a. Mercury
b. Venus c. Mars d. Saturn
ANSWER: d
21. When Mars is located directly behind the Earth with respect to the Sun in its orbit, we
see it at its highest in the sky. At what time of day or night does this happen?
a. at sunset
b. at midnight
c. at sunrise d. at noon
ANSWER: b
22. What was Tycho Brahe’s greatest contribution to astronomy? a. his model of the
universe
b. his telescopic observations
c. his discovery of three laws of motion
d. his 20 years of careful observations of the planets
ANSWER: d
23. What is the term for a commonly accepted set of scientific ideas and assumptions? a.
theory
b. paradigm c. hypothesis d. natural law
ANSWER: b
24. What two numbers tell us the size and shape of an ellipse? a. radius, eccentricity
b. radius, deferent
c. semi-major axis, deferent
d. semi-major axis, eccentricity ANSWER: d
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25. The orbit of planet A has an eccentricity of 0.5 and the orbit of planet B has an
eccentricity of 0.01. What can be said about the shape of the orbits of these two planets?
a. Planet A has a nearly circular orbit.
b. The orbit of planet A is more elongated than the orbit of planet B.
c. The orbit of planet B is more elongated than the orbit of planet A.
d. There is not enough information to say anything meaningful about the shape of either
orbit.
ANSWER: b
26. Which of the following describes the semi-major axis of an ellipse?
a. the ratio of the longest diameter of the ellipse to the shortest diameter of the ellipse b.
half the length of the shortest diameter of the ellipse
c. half the length of the longest diameter of the ellipse
d. the distance between the two foci of the ellipse
ANSWER: c
27. Which of the following statements is implied by Kepler’s first law of planetary motion?
a. The planets move at a constant speed at all points in their orbits.
b. The planets all move around the Earth in elliptical orbits.
c. Uniform circular motion is adequate to describe the motion of all planets.
d. The planets move in elliptical orbits around the Sun.
ANSWER: d
28. Given its orbital period of 76 years, what is the average distance of Comet Halley from
the Sun? a. 18 AU
b. 38 AU c. 51 AU d. 114 AU
ANSWER: a
29. An object has been located orbiting the Sun at a distance of 65 AU. What is the
approximate orbital period of this object?
a. 8.1 years b. 65 years
c. 524 years d. 4225 years
ANSWER: c
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30. On average, Saturn is 10 AU from the Sun. What is the approximate orbital period of
Saturn? a. 10 years
b. 32 years
c. 1000 years d. 3200 years
ANSWER: b
31. The period of Jupiter’s orbit around the Sun is approximately 12 years. What is the
approximate distance from the Sun to Jupiter?
a. 5.2 AU b. 42 AU
c. 144 AU d. 1728 AU
ANSWER: a
32. Suppose that a distant planet orbiting its sun has an orbital period of 8 years. What is
the approximate distance from the sun to the planet?
a. 1 AU
b. 4 AU
c. 10 AU d. 32 AU
ANSWER: b
33. The orbit of the planet Jupiter is an ellipse with the Sun at one focus. What is located at
the other focus? a. the Earth
b. the asteroid belt c. Saturn
d. nothing
ANSWER: d
34. The orbit of the planet Mars is an ellipse with the Sun at one focus. What is located at
the other focus? a. nothing
b. the asteroid belt c. Saturn
d. Venus
ANSWER: a
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35. The orbit of the Moon is an ellipse with the Earth at one focus. What is located at the
other focus? a. nothing
b. the asteroid belt c. comets
d. the Sun
ANSWER: a
36. A comet is found in a highly elliptical orbit with a semi-major axis equal to one
astronomical unit (AU). According to Kepler’s third law of planetary motion, what would
the sidereal period of this comet be?
a. It would be more than one year.
b. It would be one year.
c. It would be less than one year.
d. It would be 76 years; the same for every comet.
ANSWER: b
37. What does the eccentricity of a planet’s orbit describe?
a. westward motion in the night sky when observed on successive nights b. deviation in
shape when compared to a circle
c. tilt with respect to the ecliptic plane
d. the tilt of the planet’s rotational axis with respect to the ecliptic
ANSWER: b
38. Imagine you are travelling though the asteroid belt. Which of the following would you
expect to observe? a. All asteroids in the asteroid belt have shorter orbital period than
Earth.
b. Asteroids closer to Mars have longer orbital period than those closer to Jupiter.
c. All asteroids within the asteroid belt have the same orbital period.
d. Asteroids closer to Mars have shorter orbital periods than those closer to Jupiter.
ANSWER: d
39. Which of the following statements best describes Kepler’s third law of planetary
motion? a. The smaller the diameter of a planet, the faster its rotational period.
b. The orbital period of a planet is directly proportional to the diameter of the planet.
c. The smaller the orbit, the longer its orbital period.
d. The larger the orbit, the longer its orbital period. ANSWER: d
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40. Which of the following statements is implied by Kepler’s second law of planetary
motion? a. A planet should move at its greatest speed when it is closest to the Sun.
b. The most massive planets will have the greatest speed in their orbits.
c. The speed of a planet in its orbit depends on the size of the epicycle.
d. The mass of the planet determines how far the planet is from the Sun.
ANSWER: a
41. What did Galileo’s observations of a complete set of phases of Venus prove? a. that
Venus orbited the Sun
b. that the Earth orbited the Sun
c. that all of the planets orbited the Sun
d. that Venus had an atmosphere
ANSWER: a
42. Galileo’s telescopic discoveries of mountains on the Moon and spots on the Sun were
controversial because they suggested something about the Sun and Moon. What was it?
a. that they were the same kind of object
b. that they were not perfect spheres
c. that they were inhabited
d. that they orbited each other
ANSWER: b
43. What is the term for a single conjecture that can be tested? a. hypothesis
b. paradigm c. model
d. theory
ANSWER: a
44. What is the term for a description of some natural phenomenon that can't be right or
wrong, but is merely a convenient way to think about a natural phenomenon?
a. hypothesis
b. paradigm
c. model d. theory
ANSWER: c
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45. What is the term for a well supported (observationally and/or experimentally) system
of rules and principles that can be applied to a wide variety of circumstances but that is not
universally accepted?
a. hypothesis
b. paradigm
c. theory d. model
ANSWER: c
46. How did Galileo’s observations of moons orbiting Jupiter conflict with the geocentric
model of the universe of his time?
a. The moons moved in non-circular orbits about Jupiter.
b. The moons did not appear to orbit the Sun.
c. The moons did not appear to orbit the Earth.
d. The moons appeared to be too small, and therefore too far away, to be considered part of
the solar system.
ANSWER: c
47. Which of the following planets can be seen in a crescent phase when observed from the
Earth? a. Mercury and Venus
b. Venus and Mars
c. Mercury
d. Jupiter and Saturn
ANSWER: a
48. Imagine a satellite in orbit around the Earth, always at a constant distance from the
centre of the Earth. Which of its properties changes?
a. velocity
b. speed
c. acceleration d. mass
ANSWER: a
49. If your mass is 65 kg on the earth, what would your mass be on Jupiter? a. 650 lbs
b. 65 lbs c. 650 kg d. 65 kg
ANSWER: d
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50. When we say that gravitation is universal, what do we mean?
a. The Earth exerts gravitational force on objects on its surface.
b. The Earth exerts a gravitational force on its Moon and vice versa.
c. The Earth, the Moon, and the Sun exert gravitational force on each other. d. All objects
exert gravitational force on one another.
ANSWER: d
51. What was the basis for Isaac Newton’s conclusion that a force from the Earth must be
acting on the Moon? a. A force is needed to keep the Moon in motion in its orbit.
b. A force is needed to pull the Moon outward.
c. A force is needed to accelerate the Moon toward the Earth, away from straight-line
motion.
d. The Moon moved at a constant velocity in a straight line.
ANSWER: c
52. Would your mass and weight change if you went to the Moon? a. Weight would change
but mass would not.
b. Mass would change but weight would not.
c. Both would change.
d. Neither would change.
ANSWER: a
53. If the mass of the Earth decreased by a factor of 2, with no change in the radius, what
would happen to your weight?
a. It would increase by a factor of 2. b. It would increase by a factor of 4. c. It would decrease
by a factor of 2. d. It would decrease by a factor of 4.
ANSWER: c
54. If the mass of the Earth increased by a factor of 3, with no change in the radius, what
would happen to your weight?
a. It would increase by a factor of 3. b. It would increase by a factor of 6. c. It would decrease
by a factor of 3. d. It would decrease by a factor of 6.
ANSWER: a
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55. If the mass of the Earth increased by a factor of 4, with no change in the radius, what
would happen to your mass? a. It would increase.
b. It would decrease.
c. It would stay the same.
d. It would exponentially decrease to zero.
ANSWER: c
56. Gravity obeys an inverse square relation. What does this statement imply about the
force due to gravity between two masses?
a. It will increase as the distance between the two masses increases.
b. It will decrease as the square of the distance between the two masses increases. c. It will
cause the two masses to move in a straight line.
d. It will cause the two masses to orbit each other.
ANSWER: b
57. What does the force due to gravity between two objects depend on? a. the objects’
masses and velocities
b. the objects’ masses and the distance between them
c. the objects’ velocities and the distance between them
d. the objects’ distance from the Earth
ANSWER: b
58. At which lunar phase(s) are tides at their lowest? a. both new Moon and first quarter
Moon
b. both first quarter Moon and third quarter Moon c. new Moon
d. full Moon
ANSWER: b
59. When do spring tides occur?
a. at new Moon and first quarter Moon
b. at first quarter Moon and third quarter Moon c. at new Moon and full Moon
d. at third quarter Moon and full Moon
ANSWER: c
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60. Which of the following occur only when the Moon is in the first or third quarter? a. neap
tides
b. spring tides
c. total solar eclipses d. annular eclipses
ANSWER: a
61. What do we call an orbit that has the same period as the rotation period of the Earth? a.
a daily orbit
b. a lunar orbit
c. an epicycle orbit
d. a geosynchronous orbit
ANSWER: d
62. Which of the following orbits are referred to as open orbits? a. circle and spiral
b. hyperbola and parabola
c. ellipse and circle
d. ellipse and parabola
ANSWER: b
63. Ptolemy formulated a(n) ____________________ model of the solar system to predict
positions of the Sun, Moon, and planets.
ANSWER: geocentric
64. A(n) ____________________ is a circle, the centre of which moves in a circular orbit around
the Earth.
ANSWER: epicycle
65. The first modern astronomer to propose a heliocentric model for the solar system was
____________________.
ANSWER: Copernicus
66. The orbital period of Uranus is 84 years. How far is Uranus from the Sun?
ANSWER: 19AU
67. According to Kepler’s third law, a planet’s orbital period ____________________ is equal to its
average distance from the Sun ____________________.
ANSWER: squared,cubed
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68. The first observations of objects in the solar system that orbited neither the Sun nor the
Earth were made by ____________________.
ANSWER: Galileo
69. Ocean tides of low amplitude that occur at first and third quarter Moons are called
____________________.
ANSWER: neaptides
70. The Copernican model of the solar system has the planets orbiting the Sun along
elliptical paths. a. True
b. False
ANSWER: False
71. Copernicus was the first to propose that the Earth moved around the Sun. a. True
b. False
ANSWER: False
72. A scientific model can never be exactly correct. a. True
b. False
ANSWER: True
73. Many classical Greek astronomers believed the Earth could not move because they
detected no parallax. a. True
b. False
ANSWER: True
74. The Ptolemaic model of the universe was heliocentric. a. True
b. False
ANSWER: False
75. Classical Greek astronomers believed the motions of the heavens could be described by
uniform circular motion. a. True
b. False ANSWER: True
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76. Galileo used a telescope to observe the phases of Jupiter. a. True
b. False
ANSWER: False
77. If a planet orbits the Sun at a distance of 4 AU, then its orbital period is 8 years. a. True
b. False ANSWER: True
78. The force due to gravity has the mathematical form:
a. True b. False
ANSWER: True
79. The law of gravitation is termed universal because it is a property of all material objects.
a. True
b. False
ANSWER: True
80. The neap tides can only occur when the Moon’s position is at or near one of its orbital
nodes. a. True
b. False
ANSWER: False
81. The spring tides occur during the new and full lunar phases. a. True
b. False
ANSWER: True
82. Describe the differences between the Ptolemaic, Tychonian, and Copernican models of
the universe.
ANSWER: Answernotprovided.
83. Describe the Ptolemaic model of the universe. Draw a diagram of the model, showing
the major components of the model for the Earth, the Moon, the Sun, and the five planets
visible to the ancient Greeks.
ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 3 - THE ORIGIN OF MODERN ASTRONOMY
84. What are Kepler’s three laws of planetary motion? ANSWER: Answernotprovided.
85. Why were Galileo’s telescopic observations of the phases of Venus critical evidence in
favour of the Copernican theory?
ANSWER: Answernotprovided.
86. How did the geocentric model and the heliocentric model of the universe explain
retrograde motion?
ANSWER: Answernotprovided.
87. How did Tycho Brahe’s model of the universe differ from that of Ptolemy? How did
Tycho Brahe’s model of the universe differ from that of Copernicus?
ANSWER: Answernotprovided.
88. If Copernicus overthrew the geocentric universe, what did Kepler overthrow?
ANSWER: Answernotprovided.
89. What are Newton’s three laws of motion?
ANSWER: Answernotprovided.
90. Why does Ptolemy include epicycles in his model?
ANSWER: Answernotprovided.
91. Describe one observation that would disprove the Ptolemaic model and explain why it
would conflict with the model.
ANSWER: Answernotprovided.
92. Discuss which of Galileo’s observations argued against the geocentric model and which
of his discoveries argued for the heliocentric model.
ANSWER: Answernotprovided.
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CHAPTER 4 - ASTRONOMICAL TELESCOPES AND INSTRUMENTS: EXTENDING
HUMANITY’S VISION
1. Which of the following statements best describes the wavelength of a wave? a. the
measure of how strong the wave is
b. the distance between two adjacent peaks of the wave
c. the measure of how fast the wave is
d. the distance between a peak of the wave and the next trough
ANSWER: b
2. Which form of electromagnetic radiation travels fastest?
a. gamma rays
b. radio waves
c. all electromagnetic radiation travels at the same speed
d. the speed of radiation depends on the brightness of the source
ANSWER: c
3. What does the word “radiation” mean when used by scientists? a. invisible forms of light
such as X-rays and radio waves
b. the light emitted by black holes and protostars
c. high-energy particles from nuclear reactors
d. anything that spreads out from a central source
ANSWER: d
4. What does a nanometre measure? a. frequency
b. energy
c. mass
d. length
ANSWER: d
5. In which way is a photon of blue light identical to a photon of red light? a. energy
b. speed
c. wavelength d. frequency
ANSWER: b
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HUMANITY’S VISION
6. Which of the following types of light has wavelengths that are longer than the
wavelengths of visible light? a. gamma rays
b. ultraviolet
c. infrared
d. X-rays
ANSWER: c
7. What is the longest wavelength of light that can be seen with the human eye? a. 400
nanometres
b. 700 nanometres
c. 7000 nanometres
d. 3×108 m
ANSWER: b
8. How does long-wavelength visible light appear to the average human eye? a. invisible
b. green c. blue d. red
ANSWER: d
9. What is the relationship between colour and wavelength for light? a. Wavelength
increases from blue light to red light.
b. Wavelength decreases from blue light to red light.
c. All colours of light have the same wavelength.
d. Wavelength depends on intensity, not colour.
ANSWER: a
10. Which of the following sequences of electromagnetic radiation shows the order of
increasing energy correctly? a. gamma rays, X-rays, infrared, radio
b. visible, ultraviolet, X-rays, gamma rays
c. visible, microwave, radio, infrared
d. infrared, visible, radio, X-rays ANSWER: b
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HUMANITY’S VISION
11. Which of the following types of light has wavelengths that are shorter than the
wavelengths of visible light? a. gamma rays
b. radio waves
c. infrared radiation d. microwaves
ANSWER: a
12. Which of the following types of electromagnetic radiation has the smallest frequency? a.
X-rays
b. radio waves
c. visible light
d. infrared radiation
ANSWER: b
13. Which of the following types of electromagnetic radiation has the greatest energy per
photon? a. X-rays
b. radio waves
c. gamma rays
d. infrared radiation
ANSWER: c
14. Which of the following types of electromagnetic radiation has the lowest energy per
photon? a. X-rays
b. ultraviolet light
c. gamma rays
d. infrared radiation
ANSWER: d
15. Which of the following statements about the Earth’s atmosphere is true? a. The
atmosphere is transparent to most radio waves.
b. The atmosphere is opaque to most radio waves.
c. The atmosphere is transparent to X-rays.
d. The atmosphere is opaque to most visible wavelengths. ANSWER: a
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16. How does the energy of a photon relate to the other properties of light? a. Energy is
directly proportional to the wavelength of the light.
b. Energy is inversely proportional to the wavelength of the light.
c. Energy depends only on the speed of the light.
d. Energy is inversely proportional to the frequency of the light.
ANSWER: b
17. How do photons of blue light differ from photons of red light?
a. Blue light photons have more energy than photons of red light.
b. Blue light photons have a lower frequency than photons of red light. c. Blue light photons
have a longer wavelength than photons of red light. d. Blue light photons travel faster than
photons of red light.
ANSWER: a
18. What statement below best describes the refraction of light?
a. the absorption of light as it travels though a dense, transparent material
b. the spreading out of white light according to wavelength
c. the change in direction of a light ray as it passes to a medium of different optical density
d. the change in direction of a ray of light as it reflects off a surface
ANSWER: c
19. What is a photon?
a. a type of electromagnetic radiation
b. a particle within the atmospheric window
c. a particle produced when light interacts with vacuum d. a particle of light
ANSWER: d
20. Which of the following types of electromagnetic radiation is absorbed by water lower in
the Earth’s atmosphere, but can be detected by telescopes that are on mountaintops or are
carried by aircraft?
a. infrared radiation
b. ultraviolet radiation
c. radio wave radiation d. X-ray radiation
ANSWER: a
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21. Which of the following types of electromagnetic radiation is absorbed by ozone in the
Earth’s atmosphere? a. infrared radiation
b. ultraviolet radiation
c. X-ray radiation
d. visible light
ANSWER: b
22. What is a similarity between radio and optical telescopes? a. Both can observe from the
Earth’s surface.
b. Both are usually located on mountaintops.
c. Both are usually made as refracting telescopes.
d. Both can detect radiation with charge-coupled devices.
ANSWER: a
23. Why do astronomers build radio telescopes?
a. Radio waves give a different view of the universe.
b. Radio waves from space reach the Earth’s surface.
c. Radio telescopes can detect signals from aliens.
d. Radio telescopes can be much larger than optical telescopes.
ANSWER: a
24. What type of telescope is most likely to suffer from chromatic aberration and have a low
light-gathering power? a. a small diameter reflecting telescope
b. a large diameter reflecting telescope
c. a small diameter refracting telescope
d. a large diameter refracting telescope
ANSWER: c
25. When does chromatic aberration occur in a telescope?
a. when different colours of light do not focus at the same point in a reflecting telescope
b. when different colours of light do not focus at the same point in a refracting telescope c.
when light of different wavelengths gets absorbed by the mirror in a reflecting telescope d.
when light of different wavelengths gets absorbed by the lens in a refracting telescope
ANSWER: b
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26. What type of telescope is a radio telescope? a. reflecting
b. refracting c. deflecting d. retracting
ANSWER: a
27. What type of telescope has a lens as its objective and contains no mirrors? a. deflecting
b. reflecting c. refracting d. compound
ANSWER: c
28. How is the objective of most radio telescopes similar to the objective of a reflecting
optical telescope? a. They are both bowl-shaped (concave).
b. They are both hill-shaped (convex).
c. They are typically the same size.
d. They are both made of metal.
ANSWER: a
29. What type of primary is found in a reflecting telescope? a. prism
b. mirror
c. lens
d. diffraction grating
ANSWER: b
30. You point your backyard reflecting telescope at the star Vega. Where does Vega’s light
go? a. from the primary mirror, to the secondary mirror, to the eyepiece
b. from the primary mirror to the eyepiece
c. through the primary lens, to the secondary mirror, to the eyepiece
d. through the primary lens, through the secondary lens, to the eyepiece ANSWER: a
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31. Which of the following best explains the concept of atmospheric windows?
a. Holes in the Earth’s atmosphere allow ultraviolet radiation to reach the North and South
poles.
b. X-ray radiation from space can see through the atmosphere to observe activities on the
ground.
c. Only certain wavelengths of electromagnetic radiation from space reach the Earth’s
surface.
d. The Earth’s atmosphere can be “closed” or “open” to electromagnetic radiation,
depending on the weather.
ANSWER: c
32. What is the main reason for building large optical telescopes?
1. It’s the best way to see through clouds and other light-absorbers in the atmosphere.
2. It’s the best way to collect as much light as possible from faint objects.
3. It’s the best way to nullify the blurring effects of the Earth’s atmosphere and thus
produce higher resolution images.
4. It’s the best way to magnify objects and make them brighter.
ANSWER: b
33. An astronomer takes two pictures of the same object using the Hubble Space Telescope.
One picture is taken with red light and one with blue light. Which one would you expect to
show finer details?
a. Blue light will show finer details.
b. Red light will show finer details.
c. Both should be the same.
d. The amount of detail depends on the distance to the object.
ANSWER: a
34. Which property of a telescope determines its light-gathering power? a. the focal length
of the objective
b. the focal length of the eyepiece
c. the diameter of the objective
d. the length of the telescope tube
ANSWER: c
35. What is the light-gathering power of a telescope directly proportional to? a. the
diameter of the primary mirror or lens
b. the focal length of the primary mirror or lens
c. the length of the telescope tube
d. the diameter of the eyepiece ANSWER: a
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36. Why can’t a telescope image be magnified to show any level of detail? a. Diffraction
limits the amount of detail that is visible.
b. Telescopes only view a small region of the sky.
c. Magnification depends on focal length.
d. Resolving power depends on wavelength.
ANSWER: a
37. Which of the following has the most light-gathering power?
a. a telescope of 5 centimetres diameter and focal length of 50 centimetres b. a telescope of
6 centimetres diameter and focal length of 100 centimetres c. a telescope of 2 centimetres
diameter and focal length of 100 centimetres d. a telescope of 3 centimetres diameter and
focal length of 75 centimetres
ANSWER: b
38. How is the resolving power of a telescope defined?
a. It is a measure of the minimum angular separation that can be seen with the telescope. b.
It is a measure of the amount of light that the telescope can gather in one second.
c. It is the separation between the objective and the image.
d. It is a measure of how blurry objects appear in the telescope.
ANSWER: a
39. What happens to a telescope’s light-gathering power and resolving power when you
increase its diameter? a. Its light-gathering power and resolving power both increase.
b. Its light-gathering power increases and its resolving power decreases.
c. Its light-gathering power decreases and its resolving power increases.
d. Its light-gathering power and resolving power both decrease.
ANSWER: a
40. What can be done to improve the resolving power of ground-based optical telescopes? a.
Use them at longer wavelengths.
b. Equip them with an adaptive optics system.
c. Change them from reflectors to refractors.
d. Increase their focal length. ANSWER: b
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41. The pupil of the human eye is approximately 0.8 centimetres in diameter when adapted
to the dark. What is the ratio of the light-gathering power of a 1.6 metre telescope to that of
the human eye?
a. 2 : 1
b. 20 : 1
c. 400 : 1
d. 40,000 : 1
ANSWER: d
42. What is the ratio of the light-gathering power of a 10-metre telescope to that of a 1metre telescope? a. 10 to 1
b. 1 to 10 c. 100 to 1 d. 1 to 100
ANSWER: c
43. Space telescope A has a diameter of 2.4 metres; space telescope B has a diameter of 6.5
metres. If they take pictures with the same wavelength of light, which telescope will be
better able to make separate images of two stars close together on the sky?
a. Telescope A will do better.
b. Telescope B will do better.
c. Neither one; if they work at the same wavelength, they will give the same results.
d. Neither one; even in space, telescopes cannot separate objects that are near each other.
ANSWER: b
44. Why do radio telescopes have poor resolving power?
a. Their diameters are extremely large.
b. The energy they receive is not electromagnetic radiation. c. Radio waves have long
wavelengths.
d. Radio waves travel at slow speeds.
ANSWER: c
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45. What is the term for the technique of connecting multiple telescopes together to
combine the images from each telescope?
a. resolving power b. active optics
c. adaptive optics d. interferometry
ANSWER: d
46. What is the purpose of interferometry?
a. It is used to improve the resolving power of telescopes.
b. It is used to decrease the chromatic aberration of a telescope.
c. It is used to make large X-ray and ultraviolet telescopes.
d. It allows radio telescopes to be within a few hundred feet of each other.
ANSWER: a
47. What feature of a telescope is a measure of its ability to show fine detail and depends on
the diameter of the objective?
a. light-gathering power b. focal length
c. magnifying power
d. resolving power
ANSWER: d
48. What is the main reason for positioning many radio telescopes across a large area and
combining the signals? a. to provide a backup system if one or more of the telescopes go
down
b. to produce higher resolution images
c. to prevent interference between signals from the separate telescopes
d. to compensate for the motion of objects in the sky as a result of the Earth’s rotation
ANSWER: b
49. Which feature(s) of a telescope determine its magnifying power? a. diameter of the
primary only
b. focal length of the primary only
c. primary diameter and focal length of the eyepiece
d. focal length of the primary and eyepiece ANSWER: d
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50. What is the purpose of adaptive optics?
a. to improve diffraction limit and increase magnification power for ground-based
telescopes
b. to increase the light-gathering power of ground-based telescopes
c. to compensate for the distorting effect of atmospheric turbulence in ground-based
telescopes d. to see through clouds and remove blurring for ground-based telescopes
ANSWER: c
51. Which of the following statements best explains why stars twinkle?
a. variations in the diffraction limit of the atmosphere
b. bending of light rays by turbulent layers in the atmosphere
c. differential bending of visible wavelengths in the middle atmosphere d. bending of
ultraviolet rays as they reflect back into space
ANSWER: b
52. Radio telescopes are affected by interference from human-made radio devices. What is
the equivalent problem for optical telescopes?
a. light pollution
b. seeing
c. clouds and water vapour d. atmospheric turbulence
ANSWER: a
53. Which of the following could you use to study black holes? a. a gamma-ray telescope on
a mountaintop
b. an infrared telescope at sea level on Earth
c. a radio telescope in space
d. an X-ray telescope in space
ANSWER: d
54. Why do astronomers build telescopes on tops of mountains?
a. There is less air to dim the light.
b. The weather is better on mountaintops.
c. Electronic cameras work better when there is less oxygen in the air. d. Mountaintops are
closer to objects in space.
ANSWER: a
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55. A new generation of ground-based telescopes are currently being built to overcome the
limitations of the older large telescopes. How are these different from previous telescopes?
a. They can eliminate light pollution.
b. They can detect X-rays.
c. They use computers to control the shape of the mirror. d. They can see through clouds.
ANSWER: c
56. An astronomy graduate student takes a long-exposure picture with a CCD camera but
forgets to turn on the telescope tracking. What will the picture look like?
a. The picture will be blank.
b. The picture will be blurry.
c. The picture will have long, thin star trails. d. The picture will have many false colours.
ANSWER: c
57. What is the outstanding construction feature of the largest single-dish radio telescope?
a. It is suspended on cables in a valley.
b. It is buried deep in a mine underground.
c. It is orbiting in space.
d. It is suspended from balloons in the upper atmosphere.
ANSWER: a
58. What is “false” about false-colour images?
a. They are images created by computer simulations.
b. The colours do not represent the colours humans can see. c. The colours are exaggerated
for visual effect.
d. They are images created by artists, not astronomers.
ANSWER: b
59. Which of the following has a few million light-sensitive diodes in an array typically
measuring about one centimetre square?
a. photographic plate
b. spectrograph
c. charge-coupled device d. grating
ANSWER: c
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60. What is Very Long Baseline Interferometry (VLBI)?
a. a method to observe the largest possible areas of the sky in radio waves
b. a method to observe the largest wavelength optical light
c. linking optical telescopes in different hemispheres to observe the whole sky d. linking
radio telescopes together electronically to provide very high resolution
ANSWER: d
61. Suppose that you wanted to know how bright a star was at several different
wavelengths of light. What kind of instrument would you use?
a. a spectrograph
b. a seismograph
c. a photograph
d. a chromatic aberrator
ANSWER: a
62. What is the term for a piece of glass with many small parallel lines etched on its surface,
used to produce a spectrum?
a. spectrograph
b. grating
c. charge-coupled device d. prism
ANSWER: b
63. Far-infrared telescopes have to be cooled, but visible-light telescopes do not. Why not?
a. Far-infrared radiation is absorbed by the Earth’s atmosphere.
b. Visible-light telescopes detect light from cool objects.
c. Far-infrared telescopes can only work in space.
d. Telescopes are not hot enough to emit visible light.
ANSWER: d
64. Why must far-infrared astronomy be done from high-flying aircraft or spacecraft? a.
Far-infrared radiation is absorbed low in the Earth’s atmosphere.
b. Far-infrared photons are quite energetic.
c. Far-infrared photons have long wavelengths.
d. Far-infrared radiation is reflected from the top of the Earth’s atmosphere. ANSWER: a
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65. Which of the following telescope types must be used above the Earth’s atmosphere? a.
an optical telescope
b. a refracting telescope
c. an X-ray telescope
d. a radio telescope
ANSWER: c
66. Which of the following types of radiation from a star cannot penetrate the Earth’s
atmosphere and reach the ground?
a. ultraviolet b. visible
c. infrared d. nuclear
ANSWER: a
67. What is the most important reason for putting an optical telescope in space?
a. An optical telescope in space observes radiation that does not pass through the Earth’s
atmosphere. b. A telescope in space is closer to the objects it observes.
c. Telescopes in space are not subject to the blurring effects of the Earth’s atmosphere.
d. An optical telescope in space can be made much larger than one on the ground.
ANSWER: c
68. The Earth’s atmosphere blocks most forms of electromagnetic radiation from entering,
except for _______________ ___________ and ______________ _____________.
ANSWER: visible light; radio waves OR radio waves, visible light
69. A(n) ____________________ telescope has an objective that is a lens.
ANSWER: refracting
70. The main lens or mirror of a telescope is called the ____________________.
ANSWER: primary
71. A(n) _________________ _____________________ uses a mirror as its objective.
ANSWER: reflectingtelescope
72. Refracting telescopes suffer from ____________________ aberration.
ANSWER: chromatic
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73. The _______________ _____________ is a measure of the finest detail that can be seen in an
image.
ANSWER: resolution/resolvingpower resolution power
resolving power
74. The process of combining signals from separate telescopes to improve resolution is
called _______________________.
ANSWER: interferometry
75. The ____________________ ____________ of a telescope is determined by the size of the
objective.
ANSWER: light-gatheringpower
76. The ____________________ is a measure of the clarity of the atmosphere.
ANSWER: seeing
77. The ____________________ is a measure of how many times larger the angular size of an
object appears through a telescope.
ANSWER: magnification
78. The diagram below illustrates the layout and light path of a reflecting telescope of the
____________________ design.
ANSWER: Cassegrain
79. A(n) ____________________ is used to measure the brightness and colour of stars.
ANSWER: photometer
80. 300 nanometre light has a lower frequency than 500 nanometre light. a. True
b. False ANSWER: False
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81. The largest optical telescope ever constructed was a refracting telescope. a. True
b. False
ANSWER: False
82. X-rays easily penetrate the Earth’s atmosphere and reach the ground from space. a. True
b. False
ANSWER: False
83. Light can behave like a particle or like a wave. a. True
b. False
ANSWER: True
84. The amount of energy a photon carries depends on its wavelength. a. True
b. False
ANSWER: True
85. Reflecting telescopes are no longer popular with astronomers because they are
expensive and suffer from chromatic aberration.
a. True
b. False
ANSWER: False
86. The sidereal drive on a telescope mounting must turn the telescope eastward about the
polar axis. a. True
b. False
ANSWER: False
87. One of the advantages of charge-coupled devices (CCDs) over photographic plates is
that a CCD can record bright and faint objects on the same exposure.
a. True
b. False
ANSWER: True
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88. Telescopes observing in the far ultraviolet can be carried in high-flying aircraft. a. True
b. False
ANSWER: False
89. Interferometry is easiest to use with telescopes that observe at very short wavelengths.
a. True
b. False
ANSWER: False
90. In a reflecting telescope, the objective is a mirror. a. True
b. False
ANSWER: True
91. All radio telescopes are refracting telescopes. a. True
b. False
ANSWER: False
92. The angular resolution of a telescope is never less than its diffraction limit. a. True
b. False
ANSWER: True
93. The Earth’s atmosphere is opaque to radio waves. a. True
b. False
ANSWER: False
94. The light-gathering power of a telescope increases as the size of the objective increases.
a. True
b. False
ANSWER: True
95. How do atmospheric windows limit observations made from the Earth’s surface?
ANSWER: Answernotprovided.
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96. Why are nearly all recently built astronomical telescopes reflectors instead of
refractors? ANSWER: Answernotprovided.
97. What causes chromatic aberration? Does it occur in reflecting telescopes? Why or why
not? ANSWER: Answernotprovided.
98. What advantages does a large-diameter astronomical telescope have over a telescope of
a smaller diameter? ANSWER: Answernotprovided.
99. How do electronic cameras resemble photographic plates? How do they differ? ANSWER:
Answernotprovided.
100. How does adaptive optics work? Explain. ANSWER: Answernotprovided.
101. Why might astronomers some day establish an observatory on the Moon? Why would
radio astronomers prefer the far side of the Moon for their observatory?
ANSWER: Answernotprovided.
102. How does the nature of radio waves make it possible for a radio telescope to use a wire
mesh surface? Would you expect millimetre-wavelength telescopes to need smoother
surfaces than typical radio dishes? Why or why not?
ANSWER: Answernotprovided.
103. Why can infrared telescopes operate from high-flying aircraft and high mountaintops,
whereas X-ray telescopes must be placed in orbit?
ANSWER: Answernotprovided.
104. Why must telescopes that observe in the far infrared be cooled?
ANSWER: Answernotprovided.
105. List the advantages the Hubble Space Telescope has over ground-based telescopes.
ANSWER: Answernotprovided.
106. If the magnification of a telescope can be changed simply by exchanging eyepieces,
why can't you just magnify objects to very large sizes just by choosing an appropriate
eyepiece?
ANSWER: Answernotprovided.
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107. Explain why the majority of large modern telescope are reflectors. ANSWER:
Answernotprovided.
108. Explain how interferometry works. ANSWER: Answernotprovided.
109. List three sources of light pollution and explain how they affect astronomical
observations. ANSWER: Answernotprovided.
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1. How can the density of the Sun be measured?
a. by using the density of hydrogen as measured on Earth
b. by analysing samples of the solar wind
c. by using the amount of area covered by Venus during a transit d. by using Newton’s laws
and the Sun’s diameter
ANSWER: d
2. Which two quantities are needed to calculate density of any object? a. mass and volume
b. temperature and diameter
c. mass and temperature
d. volume and temperature
ANSWER: a
3. What is the definition of Absolute Zero?
a. zero degrees Celsius
b. the temperature at which no thermal energy can be extracted from atoms c. the
temperature at which water freezes
d. the temperature at which molecules split into atoms
ANSWER: b
4. The temperature of an object is 273K. What is the temperature in degrees Celsius? a. 273
b. -273 c. 0
d. 373
ANSWER: c
5. The temperature of an object is 373K. What is the temperature in degrees Celsius? a. 100
b. -100 c. 0
d. -373
ANSWER: a
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6. The temperature of an object is 100K. What is the temperature in degrees Celsius? a. -273
b. -173 c. 173 d. 273
ANSWER: b
7. What makes up the neutral hydrogen atom? a. one proton and one neutron
b. one proton
c. one proton, one neutron, and one electron d. one proton and one electron
ANSWER: d
8. What is the temperature of an object from which no heat energy can be extracted? a. 0
Kelvin
b. 100 Kelvin
c. 0° Celsius
d. 100° Celsius
ANSWER: a
9. Summer temperatures on Mars can reach 310 K. How would humans deal with such a
temperature on Earth? a. This temperature is so low that a human would freeze to death.
b. This is a Canadian winter temperature; humans could survive with a winter jacket and
boots.
c. This is a Canadian summer temperature; humans could be comfortable in shorts and a Tshirt.
d. This temperature is so high that a human would die of heatstroke.
ANSWER: c
10. Which of the following contains two or more atoms that are bound together by
exchanging or sharing electrons with each other?
a. nucleus
b. ion
c. proton d. molecule
ANSWER: d
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11. The surface temperature of the Sun is about 5800K. Based on this temperature, what is
the expected peak wavelength of radiation?
a. orange
b. green
c. yellow d. red
ANSWER: b
12. What does a non-ionized atom always contain? a. the same number of protons and
neutrons
b. the same number of protons and electrons
c. twice as many protons as neutrons
d. twice as many neutrons as protons
ANSWER: b
13. Which of the following measures the average speed of the particles (atoms or
molecules) in a gas? a. heat
b. composition c. temperature
d. binding energy
ANSWER: c
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Spectra
14. A plot of the continuous spectra of four different stars is shown in the figure. Based on
these spectra, which of the stars is the hottest?
a. Star A
b. Star B
c. Star C d. Star D
ANSWER: a
15. A plot of the continuous spectra of four different stars is shown in the figure. Based on
these spectra, which of the stars has the lowest temperature?
a. Star A
b. Star B
c. Star C d. Star D
ANSWER: d
16. The Sun emits its maximum intensity of light at about 520 nm. According to Wien’s Law,
at what wavelength would the maximum intensity be for a star with a surface temperature
twice that of the Sun?
a. 260 nm
b. 1040 nm
c. 5800 nm d. 11600 nm
ANSWER: a
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17. The Sun emits its maximum intensity of light at about 520 nm. According to Wien’s Law,
what would the temperature of a star that emits its maximum intensity at 1040 nm be?
a. 1040 K
b. 2900 K
c. 5800 K d. 10400 K
ANSWER: b
18. What is the sequence of star colours in order of increasing temperature? a. red, yellow,
blue
b. red, blue, yellow
c. yellow, red, blue
d. blue, yellow, red
ANSWER: a
19. The Stefan-Boltzmann law says that hot objects emit energy proportional to the fourth
power of their temperature. One star has a temperature of 30,000 K and another star has a
temperature of 6,000 K. Compared to the cooler star, how much more energy per second
will the hotter star radiate from each square metre of its surface?
a. 5 times as much
b. 25 times as much c. 625 times as much
d. 1.3×1015 times
ANSWER: c
20. Is it possible for a red star to emit more energy than a blue star?
a. No, because the red star has a lower temperature.
b. Yes, if the red star has a larger area.
c. Yes, if the red star has a larger wavelength of maximum intensity. d. No, because red stars
are less massive than blue stars.
ANSWER: b
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21. The Sun contains a lot of hot gas, so why do we observe an absorption spectrum rather
than an emission spectrum from it?
1. The ionized gas in the photosphere emits a continuous spectrum, which the
chromosphere changes into an
absorption spectrum.
2. The ionized gas in the photosphere emits an absorption spectrum.
3. The Sun’s photosphere is cooler than the layers below it.
4. The Sun’s photosphere is hotter than the layers below it.
ANSWER: c
22. How is it possible that you could fly a very-well-insulated spaceship through the Sun’s
photosphere? a. The photosphere is less than 500 km deep.
b. The photosphere is made of hydrogen gas.
c. The photosphere has a very low temperature.
d. The photosphere has a very low density.
ANSWER: d
23. Where does most of the visible light we see coming from the Sun originate? a. the
chromosphere
b. the photosphere
c. the corona
d. the sunspots
ANSWER: b
24. What is the explanation for the pattern of granulation seen on the visible surface of the
Sun?
a. The granules form the base of a circulation pattern that extends from the photosphere to
the outer corona. b. The granules are regions of nuclear energy generation in the Sun's
photosphere.
c. Each granule contains a strong magnetic field, which compresses and heats the gas
underneath it.
d. The granules are the tops of hot gases that have risen from the Sun's convective zone.
ANSWER: d
25. What is the phase of matter in the Sun? a. plasma
b. gas c. liquid d. solid
ANSWER: a
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26. How does gas move within granules on the solar surface?
1. Gas moves upward in the centres of some cells and downward in others; the gas
cools as it passes between
individual granules.
2. The gas is actually motionless. The dark regions are absorption features from gases
in the photosphere.
3. Gas moves upward in the bright cell centres and downward around the darker
edges.
4. Gas moves downward in the bright cell centres and upward around the darker
edges.
ANSWER: c
27. What is found in the centres of granules?
a. hot material rising to the photosphere from below
b. cool material falling from the photosphere to the regions below c. material that is fainter
and hotter than its surroundings
d. material that is brighter and cooler than its surroundings.
ANSWER: a
28. What causes granulation? a. sunspots
b. rising and sinking gases below the photosphere c. shock waves in the corona
d. the solar wind flowing away from the corona
ANSWER: b
29. What is responsible for binding the electrons to the nucleus? a. Kirchhoff's law
b. Wien’s law
c. Coulomb force
d. Balmer series
ANSWER: c
30. What is the binding energy?
a. ionization that occurs within the atom
b. the energy that holds the atom together
c. the energy of quantum effects within the atom d. the energy that causes excitation of the
atom
ANSWER: b
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31. What is the process of removing an electron from a stable nucleus called? a. ionization
b. Doppler broadening c. collisional broadening d. a red shift
ANSWER: a
32. Which of the following is a set of rules that describes how atoms and subatomic
particles behave? a. Kirchhoff's law
b. the Coulomb force
c. quantum mechanics
d. the binding energy
ANSWER: c
33. What is the term for atoms that have the same number of protons but a different
number of neutrons? a. ions
b. molecules
c. nuclear pairs d. isotopes
ANSWER: d
34. If you move an electron from a lower energy level to a higher energy level within an
atom, how would you describe that atom?
a. The atom is ionized.
b. The atom is dissociated.
c. The atom is excited.
d. The atom is neutralized.
ANSWER: c
35. What causes an atom to become excited? a. emitting a photon
b. colliding with another atom or electron c. reflecting a photon
d. gaining an extra electron ANSWER: b
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Photon
36. In the diagram, which of the transitions would absorb a photon with the least energy
(longest wavelength)? a. Transition 1
b. Transition 2 c. Transition 3 d. Transition 4
ANSWER: d
37. In the diagram, which of the transitions would absorb a photon with the greatest energy
(shortest wavelength)? a. Transition 1
b. Transition 2 c. Transition 3 d. Transition 4
ANSWER: c
38. What state must an atom be in for it to emit a photon? a. ionized
b. excited c. ground d. isotopic
ANSWER: b
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39. What is the lowest energy level in an atom called? a. the absolute zero temperature
b. the ground state
c. the ionization level
d. the energy level from which the Paschen series of hydrogen originates ANSWER: b
40. The energy of the first level in an atom is 2.2×10-18 J, and the energy of the second
energy level is 1.6×10-18 J. What is the energy of the photon that is emitted if an electron
moves from the second level to the first?
a. 3.5×10-36 J b. 6.0 ×10-18 J c. 3.5×10-18 J d. 6.0×10-19 J
ANSWER: d
41. You are standing near a railway track and a train is moving toward you at 100 kph and
blowing its whistle. What will you notice as the train moves past you?
a. As the train approaches, the horn will sound lower in pitch than when the train is moving
away.
b. As the train approaches, the horn will sound higher in pitch than when the train is
moving away.
c. As the train approaches, the headlight will appear bluer than when the train is moving
away. d. As the train approaches, the headlight will appear redder than when the train is
moving away.
ANSWER: b
42. The Doppler effect means that the motion of a object affects the light emitted from it.
What result does the Doppler effect cause?
a. It shifts the wavelength of spectral lines.
b. It changes the speed of light emitted from the object.
c. It makes the object appear hotter. d. It makes the object appear cooler.
ANSWER: a
43. What everyday object is an example of a place where electrons jump through energy
levels and emit energy? a. the full Moon
b. a gas stove
c. a neon sign
d. an incandescent light bulb ANSWER: c
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44. A certain spectral line of hydrogen has a wavelength of 410.2 nm when observed in the
laboratory. If the same line appears in a star’s spectrum at 410.0 nm, what can you
conclude about the motion of the star?
a. The star is moving away from the observer.
b. The star is moving toward the observer.
c. The star is moving but the direction is not known.
d. The star is not moving toward or away from the observer.
ANSWER: b
45. The Hγ line has a wavelength of 434.0 nm when observed in the laboratory. If the Hγ
line appears in a the spectrum of a star moving away from you, at what wavelength will you
observe the line?
a. less than 434 nm
b. 434.0 nm
c. greater than 434 nm
d. the wavelength depends on the composition of the star
ANSWER: c
46. Which of the following is a plausible example of a Doppler blueshift?
a. A star appears to have a much higher temperature when moving toward the Earth than
when moving away. b. An ambulance’s siren changes to a higher pitch as it speeds toward
you.
c. A star’s colour becomes redder as it moves away from the Earth.
d. A moving train’s whistle shifts to a frequency so high that humans can’t hear it.
ANSWER: b
47. Which of the following can be measured by using the Doppler Effect? a. the apparent
speed of an airplane moving across the sky
b. the apparent velocity of a star across the sky
c. the apparent velocity of a planet across the sky
d. the radial velocity of a star ANSWER: d
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Light
48. The diagram illustrates a light source, a gas cloud, and three different lines of sight (the
observer is located at the numbered positions). Along which line of sight would an
observer see an absorption spectrum?
a. 1
b. 2
c. 3 ANSWER: c
49. The diagram illustrates a light source, a gas cloud, and three different lines of sight (the
observer is located at the numbered positions). Along which line of sight would an
observer see a continuous spectrum?
a. 1
b. 2
c. 3
ANSWER: a
50. The diagram illustrates a light source, a gas cloud, and three different lines of sight (the
observer is located at the numbered positions). Along which line of sight would an
observer see an emission spectrum?
a. 1
b. 2
c. 3 ANSWER: b
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51. What is the term for the absorption lines in the visible portion of the spectrum of a star
that are produced by hydrogen?
a. Lyman series b. Balmer series c. Paschen series d. Brackett series
ANSWER: b
52. What are the three layers of the Sun's atmosphere, in order of increasing distance from
the surface? a. corona, chromosphere, photosphere
b. photosphere, corona, chromosphere
c. photosphere, chromosphere, corona
d. chromosphere, photosphere, corona
ANSWER: c
53. etermined from the spectrum of a star, without additional information? a. radial velocity
b. core temperature
c. distance
d. velocity across the sky
ANSWER: a
54. Why does each element have its own set of characteristic absorption lines? a. The
temperature of each element varies.
b. Elements can exist in different forms of matter.
c. Electron energy levels differ for each element.
d. Each element has a different mass.
ANSWER: c
55. Why is Cecilia Payne’s Ph.D. thesis sometimes called “the most important in
astronomy”? a. She was the first person to show that the Sun is mostly hydrogen.
b. She was the first person to analyze spectra of stars.
c. Her analysis of stellar spectra showed that stars generate their own light.
d. Her analysis of the Sun’s spectrum resulted in the discovery of helium. ANSWER: a
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56. Would you expect to see hydrogen Balmer lines in the spectra of stars with
temperatures of 3200 K?
a. Yes; these stars are so hot that most of the hydrogen is ionized and the atoms cannot
absorb energy. b. No; these stars are so cool that nearly all of the electrons in the hydrogen
atom are in the ground state. c. No; stars of this temperature are too cool to produce an
absorption spectrum.
d. Yes; stars of this temperature are too hot to produce an absorption spectrum.
ANSWER: b
57. Would you expect to see hydrogen Balmer lines in the spectra of stars with
temperatures of 45,000 K? a. No; these stars are so hot that most of the hydrogen is ionized
and the atoms cannot absorb energy.
b. Yes; these stars are so cool that nearly all of the electrons in the hydrogen atom are in the
ground state. c. Stars of this temperature are too cool to produce an absorption spectrum.
d. Stars of this temperature are too hot to produce an absorption spectrum.
ANSWER: a
58. What are the two most abundant elements in the Sun? a. nitrogen and oxygen
b. hydrogen and helium
c. carbon and hydrogen
d. carbon and nitrogen ANSWER: b
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Name: Class: Date: CHAPTER 5 - THE SUN: THE CLOSEST STAR
Sun
59. The diagram shows a plot of the temperature of the Sun as a function of distance above
the bottom of the photosphere. At what distance above the bottom of the photosphere does
the temperature of the Sun change the most rapidly with distance?
a. 400 km
b. 1,000 km
c. 2,300 km
d. 2,500 km to 4,000 km
ANSWER: c
60. The diagram shows a plot of the temperature of the Sun as a function of distance above
the bottom of the photosphere. What is the temperature of the Sun at a height of 2,000 km?
a. 500 K
b. 900 K
c. 5,000 K d. 9,000 K
ANSWER: d
61. The diagram shows a plot of the temperature of the Sun as a function of distance above
the bottom of the photosphere. At what height above the bottom of the photosphere is the
temperature of the Sun the coolest? a. 500 km
b. 1,000 km
c. 2,300 km
d. 2,500 km to 4000 km
ANSWER: a
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62. As the Moon covers the solar disk during a solar eclipse, a flash spectrum of the Sun's
chromosphere can be recorded. This flash spectrum reveals an emission spectrum and
provides information on the properties of the chromosphere. As the Moon moves from the
inner chromosphere to the outer chromosphere, the spectral lines present in the flash
spectrum change. What is going on in the chromosphere as the distance from the
photosphere increases that produces the changes in the flash spectrum?
a. temperature and density both decrease
b. temperature decreases and density increases c. temperature increases and density
decreases d. temperature and density both increase
ANSWER: c
63. Which of the following describes the kind of light used to produce a filtergram, a
photograph of the Sun's surface? a. a wide band of wavelengths in the infrared
b. a wide band of wavelengths in the ultraviolet
c. a narrow band of Zeeman effect wavelengths
d. a narrow band of wavelengths in a specific spectral line
ANSWER: d
64. Which of the following is a property of the Sun’s chromosphere? a. hotter than the
photosphere
b. is above the corona
c. is below the visible surface of the Sun
d. produces a coronal filtergram
ANSWER: a
65. Where are spicules most easily visible?
a. at the solar equator, in the lowest levels of the photosphere
b. at the centres of sunspots
c. in the corona near the north and south poles of the Sun during a total solar eclipse d. in
filtergrams of the solar chromosphere
ANSWER: d
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Name: Class: Date: CHAPTER 5 - THE SUN: THE CLOSEST STAR
66. What has a negative charge and a mass about 1800 times smaller than a proton? a. a
neutron
b. an electron c. a molecule d. a nucleus
ANSWER: b
67. Which of the following is the term for the hot gases that are the moving extension of the
Sun's corona? a. solar wind
b. prominences c. supergranules d. spicules
ANSWER: a
68. What do astronomers believe heats up the corona and chromosphere of the Sun? a.
shock waves rising from below the photosphere
b. the solar wind
c. sunspots
d. high energy particles being accelerated by the Sun’s magnetic field
ANSWER: d
69. How can the corona of the Sun be observed? a. during a lunar eclipse
b. with a coronagraph
c. using filtergrams
d. using the Zeeman effect
ANSWER: b
70. What does helioseismology measure? a. the height of the Sun’s corona
b. the strength of the solar wind
c. magnetic fields of sunspots
d. vibrations on the Sun’s surface ANSWER: d
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71. What is differential rotation of the Sun?
a. Heating in the chromosphere and corona makes them hotter than the photosphere.
b. A magnetic dynamo operates inside the Sun.
c. The equatorial regions of the Sun rotate more rapidly than the polar regions.
d. The rotation of the Sun's southern and northern hemispheres goes in opposite directions.
ANSWER: c
72. What occurs when a rapidly rotating conductor is stirred by convection to produce a
magnetic field? a. dynamo effect
b. Zeeman effect
c. Babcock effect
d. aurora
ANSWER: a
73. What pattern of movement is found in the rotation of the Sun’s photosphere?
a. fastest at the equator, slower at mid-latitudes, and slowest near the poles
b. slowest at the equator, faster at mid-latitudes, and fastest near the poles
c. fastest at the equator, and slowest at mid-latitudes and the poles, which travel at the
same speed d. the same speed regardless of latitude
ANSWER: a
74. Why is the temperature at the region of a sunspot cooler than the photosphere?
1. Sunspots are holes in the photosphere that reveal the lower-temperature gases in
the deeper layers.
2. Sunspots represent points where streams of cool gas from the corona lower the
temperature in those regions of the photosphere.
3. Powerful magnetic fields in the sunspots act upon the atoms of the photosphere to
prevent them from emitting light.
4. Powerful magnetic fields in the sunspots inhibit the convective flow of the gases of
the photosphere downward, allowing the area to cool for longer than would
normally be possible.
ANSWER: d
75. Where are sunspots found during a sunspot maximum? a. 15 to 30 degrees north and
south of the Sun’s equator b. evenly distributed over the Sun’s surface
c. near the Sun’s equator
d. near the poles of the Sun (latitudes 90° north and south) ANSWER: a
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76. Which of the following is affected by the sunspot cycle? a. the longitude at which most
sunspots occur
b. the number of sunspots that are visible
c. the rotation rate of the Sun's equator
d. the temperature of sunspot cores
ANSWER: b
77. How do we know that sunspots are magnetic phenomena? a. Doppler shifts in spectral
lines are observed.
b. The Zeeman effect is observed in sunspots.
c. Collisional broadening is observed in spectral lines.
d. Infrared observations indicate that the sunspots are cooler than their surroundings.
ANSWER: b
78. Why do sunspots appear dark?
a. Regions of the photosphere are obscured by material in the chromosphere. b. Shock
waves move through the photosphere.
c. The strong magnetic field inhibits the currents of hot gas rising from below. d. They
radiate their energy into space faster than the rest of the photosphere.
ANSWER: c
79. A recent sunspot maximum occurred in 2001. What would you predict would be the
year of the sunspot maximum that immediately follows the 2001 maximum if the solar
cycle continues?
a. 2010
b. 2012
c. 2018 d. 2023
ANSWER: b
80. What is (are) produced by atomic transitions in the presence of a strong magnetic field?
a. the Balmer series
b. dynamo effects
c. the Zeeman effect
d. isotope ratios ANSWER: c
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81. Which of the following coincided with the period known as the "little ice age" of Europe
and North America? a. Maunder sunspot minimum
b. Babcock sunspot model
c. coronal hole
d. weak solar force
ANSWER: a
82. What can astronomers use to measure magnetic fields on the Sun? a. helioseismology
b. neutrino detectors
c. a magnetic carpet
d. the Zeeman effect
ANSWER: d
83. What phenomena show evidence of the Sun's magnetic field in their looped shapes? a.
solar flares
b. sunspots
c. granules
d. prominences
ANSWER: d
84. The chromosphere and corona above sunspots are violently disturbed. Which of the
following terms best describes these regions?
a. prominence region
b. active region
c. granulation region d. auroras
ANSWER: b
85. Canada consumes about 2.0 × 1018 J of energy each year. A typical solar flare releases
5.0 × 1024 J of energy. How many years could Canada run on the energy released by this
solar flare, if all of the released energy could be used?
a. 4×10-7 years
b. about 2 years
c. 250 years
d. 2,500,000 years
ANSWER: d
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Name: Class: Date: CHAPTER 5 - THE SUN: THE CLOSEST STAR
86. Which of the following occur when energy in the solar wind guided by the Earth's
magnetic field excites gases in the Earth’s upper atmosphere?
a. coronas
b. flares
c. auroras
d. coronal holes
ANSWER: c
87. What is believed to result from energy that has been stored in a twist in the solar
magnetic field above a sunspot suddenly being released?
a. solar flare
b. supergranule
c. spicule
d. coronal hole
ANSWER: a
88. ____________________ is a measure of the amount of energy due to the motion of the
particles in a gas, liquid, or solid.
ANSWER: Heat
89. The ____________________ of a star can be determined from its colour.
ANSWER: temperature
90. If one star has a temperature of 4,000 K and another star has a temperature of 40,000 K,
how much more energy per second will the hotter star radiate from each square metre of
its surface? ____________________
ANSWER: 10,000timesasmuch
91. The peak wavelength in the continuum emission spectrum of a body is inversely
proportional to its ____________________.
ANSWER: temperature
92. Most of the light we see coming from the Sun originates in the ____________________.
ANSWER: photosphere
93. The process of removing an electron from a stable nucleus is known as
____________________.
ANSWER: ionization
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Name: Class: Date: CHAPTER 5 - THE SUN: THE CLOSEST STAR
94. In the diagram, draw the transition that would emit a photon with the smallest
wavelength.
ANSWER: alinefromtheFifthLeveltotheFirstLevel
95. When the electrons in an atom are in their lowest possible energy levels, the atom is
said to be in its ____________________ state.
ANSWER: ground
96. The ____________________ of the Sun is composed of ionized gas and produces a continuous
spectrum with a superimposed emission spectrum.
ANSWER: corona
97. The study of the oscillations of the surface and interior of the Sun is known as
____________________.
ANSWER: helioseismology
98. The dynamo effect is believed to produce the ____________________ of the Sun.
ANSWER: magneticfield
99. The ____________________ shows that sunspots are associated with magnetic activity.
ANSWER: Zeemaneffect
100. Blue stars are hotter than red stars. a. True
b. False
ANSWER: True
101. Isotopes of the same element have the same number of protons. a. True
b. False ANSWER: True
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102. Hydrogen alpha is the longest wavelength Balmer line. a. True
b. False
ANSWER: True
103. An absorption spectrum is also called a bright line spectrum. a. True
b. False
ANSWER: False
104. The Doppler effect is sensitive only to motion along the line of sight. a. True
b. False
ANSWER: True
105. An atom that has lost an electron is called an ion. a. True
b. False
ANSWER: True
106. The Lyman series lines of hydrogen all lie in the infrared. a. True
b. False
ANSWER: False
107. Hydrogen lines are weak in the spectra of hot stars because many of the hydrogen
atoms are ionized. a. True
b. False
ANSWER: True
108. The hotter an object, the more blue it appears. a. True
b. False
ANSWER: True
109. An atom is ionized if one of its electrons jumps to a higher energy level in the atom. a.
True
b. False ANSWER: False
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110. Most of the visible light from the Sun originates in the photosphere. a. True
b. False
ANSWER: True
111. In the Sun, rising currents of hot gas below the photosphere cause granulation. a. True
b. False
ANSWER: True
112. Helioseismology is the study of the differential rotation and magnetic fields of the Sun.
a. True
b. False
ANSWER: False
113. A filtergram is used to study layers below the photosphere. a. True
b. False
ANSWER: False
114. The chromosphere of the Sun has a higher temperature than the photosphere. a. True
b. False
ANSWER: True
115. The Zeeman effect shows that sunspots contain magnetic fields. a. True
b. False
ANSWER: True
116. Sunspots are hotter than the photosphere. a. True
b. False ANSWER: False
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117. The Babcock model employs differential rotation of the solar surface and a magnetic
dynamo to describe the formation of sunspots.
a. True
b. False
ANSWER: True
118. Solar flares have no known effect on the Earth. a. True
b. False
ANSWER: False
119. Solar prominences have twisted and looped shapes because of the solar magnetic field.
a. True
b. False
ANSWER: True
120. The Sun appears to rotate only because the Earth is revolving about the Sun. a. True
b. False
ANSWER: False
121. The most abundant element in the Sun is oxygen. a. True
b. False
ANSWER: False
122. The cooler an object, the more blue it appears. a. True
b. False
ANSWER: False
123. Sunspots often appear in pairs. a. True
b. False
ANSWER: True
124. Describe the appearance of each of the three types of spectra described by Kirchhoff's
laws. Describe how each of the three types of spectra is formed.
ANSWER: Answernotprovided.
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125. Describe two methods that can be used to determine the temperature of a star.
ANSWER: Answernotprovided.
126. Why do molecular bands only occur in the spectra of the coolest stars? ANSWER:
Answernotprovided.
127. Why are the Balmer lines weak in the spectra of hot and cool stars, but strong in the
spectra of intermediate temperature stars?
ANSWER: Answernotprovided.
128. Why should photons emitted by a hotter gas have, on average, shorter wavelengths
than photons emitted by a cooler gas?
ANSWER: Answernotprovided.
129. Describe two ways in which an atom can be excited.
ANSWER: Answernotprovided.
130. What would the spectrum of hydrogen look like if we could see into the ultraviolet?
ANSWER: Answernotprovided.
131. If a star's spectrum does not contain spectral lines characteristic of a certain element,
can we conclude that the star does not contain that element? Why or why not?
ANSWER: Answernotprovided.
132. Explain why the presence of spectral lines of a given element in the solar spectrum
tells us that the element is present in the Sun, but the absence of the lines would not mean
the element was absent from the Sun.
ANSWER: Answernotprovided.
133. What does granulation tell us about the layers below the Sun’s photosphere?
ANSWER: Answernotprovided.
134. Why does a filtergram reveal details in higher layers of the solar atmosphere?
ANSWER: Answernotprovided.
135. What evidence do we have that the chromosphere is hotter than the photosphere?
ANSWER: Answernotprovided.
136. What is the solar wind, and how does it affect objects in the solar system?
ANSWER: Answernotprovided.
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137. What evidence do we have that the sunspots are magnetic? ANSWER:
Answernotprovided.
138. What is the Babcock model? ANSWER: Answernotprovided.
139. How does the Sun's magnetic cycle affect the number, location, and polarity of
sunspots? ANSWER: Answernotprovided.
140. What is the Maunder minimum? Describe. ANSWER: Answernotprovided.
141. What effect does solar activity have on the Earth? ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 6 - THE FAMILY OF STARS
1. The parsec is defined so that a star at a distance of 1 parsec has a parallax of one
arcsecond. If a star has a parallax of 0.02 seconds of arc, what is its distance?
a. 2 parsecs
b. 5 parsecs
c. 20 parsecs d. 50 parsecs
ANSWER: d
2. The parsec is defined so that a star at a distance of 1 parsec has a parallax of one
arcsecond. If a star has a parallax of 0.05 seconds of arc, what is its distance?
a. 2 parsecs
b. 5 parsecs
c. 20 parsecs d. 50 parsecs
ANSWER: c
3. The parsec is defined so that a star at a distance of 1 parsec has a parallax of one
arcsecond. If a star is located at a distance of 10 parsecs, what is its parallax?
a. 0.1 arcseconds
b. 0.01 arcseconds
c. 1 arcsecond d. 10 arcseconds
ANSWER: a
4. The parsec is defined so that a star at a distance of 1 parsec has a parallax of one
arcsecond. If a star is located at a distance of 40 parsecs, what is its parallax?
a. 0.25 arcseconds
b. 0.025 arcseconds
c. 0.04 arcseconds d. 0.05 arcseconds
ANSWER: b
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5. How do humans use their eyes to measure relative distance by parallax?
1. By continuously focusing our eyes on distant objects, we can determine distance.
2. Since our eyes are separated, the brain interprets the relative look angles of the two
eyes in terms of distance to the object viewed.
3. Our eyes can measure the time it takes light to travel from an object, and from this
we get distance.
4. As we move our heads from side to side, our brain compares angles from each of
these positions to work out the distance to the object viewed.
ANSWER: b
6. How can we tell that some stars are relatively close to us in the sky?
1. Some stars are occasionally eclipsed by the Moon, so they must be nearby.
2. Some stars vary in brightness caused by sunspots that we can see because they are
so close.
3. Some stars appear to be extremely bright and must therefore be very close to us.
4. Some stars appear to move periodically back and forth against the background stars
because of the Earth's movement around the Sun.
ANSWER: d
7. What would make parallax easier to measure? a. the Earth's orbit being larger
b. the stars being farther away
c. the Earth moving faster along its orbit
d. stars moving faster in their orbits
ANSWER: a
8. If two stars are emitting the same amount of light, how will the star that is farther away
appear? a. brighter
b. dimmer c. redder d. bluer
ANSWER: b
9. What is absolute visual magnitude?
a. the luminosity of a star observed from Earth
b. the luminosity of a star observed from a distance of 1000 parsecs
c. the apparent magnitude of a star observed from a distance of 10 parsecs d. the apparent
magnitude of a star observed from Earth
ANSWER: c
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10. Absolute magnitude is defined as the apparent magnitude that a star would have if
observed at a distance of 33 light-years. Consider a star at a distance of 350 light-years that
has an apparent magnitude of +5. What would its absolute magnitude be?
a. It would be less than +5.
b. It would be exactly +5.
c. It would be greater than +5.
d. More information on the star’s luminosity would be required to answer this question.
ANSWER: a
11. What aspect of a star is a measure of the total energy radiated by the star in one second?
a. apparent visual magnitude
b. luminosity class
c. spectral type
d. luminosity
ANSWER: d
12. Which stars have a large positive absolute magnitude? a. stars of high luminosity
b. stars of low luminosity
c. nearby stars
d. distant stars
ANSWER: b
13. If you compare two stars, which one will always have the greater luminosity?
a. The one with the larger radius will always have the greater luminosity.
b. The one with the higher surface temperature will always have the greater luminosity. c.
The one with the smaller absolute magnitude will always have the greater luminosity. d.
The one with the largest distance will always have the greater luminosity.
ANSWER: c
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14. The nearest star, Proxima Centauri, is about four light-years away and has a luminosity
about 0.001 times that of the Sun. If Proxima Centauri were at a distance of one light-year
instead of four, how much brighter would it appear in the sky?
a. twice as bright
b. four times as bright c. 16 times as bright
d. 4000 times as bright
ANSWER: a
15. How does a star’s surface temperature determine the appearance of its spectrum?
a. Surface temperature affects which elements are solid, liquid, or gaseous.
b. Surface temperature determines the luminosity of the star.
c. Surface temperature affects which elements can escape from the surface of the star. d.
Surface temperature determines the velocity of collision rates of atoms and ions.
ANSWER: d
16. What is the most accurate way to determine the surface temperature of a star?
a. Study the pattern of absorption lines from various atoms.
b. Study the relative intensities of light measured through different photometric filters. c.
Study the peak wavelength of the star's continuum blackbody spectrum.
d. Study the pattern of emission lines on the star's spectrum.
ANSWER: a
17. Which of the following can the strength of spectral lines tell you about a star? a. the
radius
b. the distance
c. the temperature
d. the visual magnitude
ANSWER: c
18. You observe medium hydrogen Balmer lines, as well as neutral helium spectral features,
in a star. What is the most likely spectral class of this star?
a. G
b. M
c. F d. B
ANSWER: d
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19. You observe medium hydrogen Balmer lines, as well as neutral helium spectral features,
in a star. What is the approximate surface temperature of this star?
a. 3000 K
b. 10 000 K
c. 20 000 K d. 5500 K
ANSWER: c
20. What is the spectral sequence in order of decreasing temperature? a. OBAFGKM
b. OBAGFKM
c. BAGFKMO
d. ABFGKMO
ANSWER: a
21. What is the spectral sequence in order of increasing temperature? a. MKFAGBO
b. BAFGKMO
c. MKGFABO
d. ABFMKGO
ANSWER: c
22. Which of the following can we use to determine the surface temperature of a star? a.
determining if the star has a companion star
b. studying its line absorption spectrum
c. measuring the star’s distance
d. measuring the star’s parallax ANSWER: b
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Table 1
Star Name Spectral Type
αFor F8 ο Cet M7 γ Tri A0
ξPer O7
23. The table lists the spectral types for each of four stars. Which star in this table would
have the lowest surface temperature?
a. α For b. ο Cet c. γ Tri d. ξ Per
ANSWER: b
24. The table lists the spectral types for each of four stars. Which star in this table would
have the highest surface temperature?
a. α For b. ο Cet c. γ Tri d. ξ Per
ANSWER: d
25. What properties of a star determine its luminosity? a. distance and diameter
b. temperature and distance
c. temperature and diameter
d. apparent magnitude and temperature
ANSWER: c
26. How do we know that giant stars are larger in diameter than the Sun? a. They are more
luminous but have about the same temperature.
b. They are less luminous but have about the same temperature.
c. They are hotter but have about the same luminosity.
d. They are cooler but have about the same luminosity. ANSWER: a
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27. Sirius A and B are two stars at the same distance from the Earth. In this binary system,
Sirius A is much brighter but Sirius B is much hotter. From this information, what can you
conclude about the two stars?
a. Sirius B must be much smaller than Sirius A.
b. Sirius B must be much larger than Sirius A.
c. Sirius B must be much more massive than Sirius A. d. Sirius B must be much less massive
than Sirius A.
ANSWER: a
28. In a Hertzsprung-Russell diagram, where are the stars with the smallest radius found? a.
in the upper left corner
b. in the upper right corner
c. in the lower left corner
d. in the lower right corner
ANSWER: c
29. In a Hertzsprung-Russell diagram, where are 90 percent of all the stars found? a. in the
giant region
b. in the supergiant region
c. on the dwarf sequence
d. on the main sequence
ANSWER: d
30. The star named Sheat is of spectral type M2 and luminosity class II. Based on this
information, how does Sheat compare to the Sun?
a. Sheat is cooler and larger than the Sun.
b. Sheat is cooler and smaller than the Sun.
c. Sheat is hotter and more luminous than the Sun. d. Sheat is hotter and larger than the Sun.
ANSWER: a
31. The star named Circini has the spectral type and luminosity class of O 8.5 V. Based on
this information, how does Circini compare to the Sun?
a. Circini is cooler and larger than the Sun.
b. Circini is cooler and smaller than the Sun.
c. Circini is hotter and more luminous than the Sun. d. Circini is hotter and less luminous
than the Sun.
ANSWER: c
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32. Where are red giant stars found in the Hertzsprung-Russell diagram? a. above the main
sequence
b. below the main sequence
c. on the lower main sequence
d. on the upper main sequence ANSWER: a
Table 2
Star Parallax (sec of arc) Spectral Type
δ Cen
HR 4758 HD 39801
9 CMa
33. Which star in a. δ Cen
b. HR 4758 c. HD 39801 d. 9 CMa
ANSWER: d
34. Which star in a. δ Cen
b. HR 4758 c. HD 39801 d. 9 CMa
ANSWER: a
35. Which star in a. δ Cen
b. HR 4758 c. HD 39801 d. 9 CMa
ANSWER: c
0.026 0.05 0.005
0.4
B2 IV G0 V M2 I
A1 V
the table is the closest to Earth?
the table has the highest surface temperature?
the table has the largest diameter?
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Hertz
36. When compared to stars near the middle of the diagram, how are stars in the upper
right part of the Hertzsprung- Russell diagram different?
a. They are always cooler.
b. They are always larger.
c. They are always smaller.
d. They are always more massive.
ANSWER: b
37. Use the Hertzsprung-Russell diagram to answer the following question: Which star in
the diagram is most like the Sun?
a. Alnilam b. Arcturus c. HR 5337 d. Sirius B
ANSWER: c
38. Use the Hertzsprung-Russell diagram to answer the following question: Which star in
the diagram has the highest surface temperature?
a. Alnilam
b. Antares
c. Arcturus d. Sirius B
ANSWER: a
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39. Use the Hertzsprung-Russell diagram to answer the following question: Which star in
the diagram has the largest absolute visual magnitude?
a. Antares
b. Arcturus
c. HR 5337 d. Sirius B
ANSWER: d
40. How is a luminosity class assigned to a star?
a. by combining the apparent magnitude with the star's parallax
b. by measuring the period of variability in the star's apparent magnitude
c. by studying the absorption line width in the spectrum of the star
d. by observing the angular size of the star's image in a photograph or digital image
ANSWER: c
41. In what kind of type A star are the hydrogen lines narrowest? a. supergiants
b. main-sequence stars c. subgiants
d. dwarfs
ANSWER: a
42. Compared with the spectral lines in the solar spectrum, how are lines in a supergiant
star’s spectrum different? a. They are narrower.
b. They are broader.
c. They are weaker.
d. They are stronger.
ANSWER: a
43. What is the most reliable way to measure the mass of a star for which the distance is
unknown? a. Apply the mass-temperature relation.
b. Measure its orbit around another star.
c. Measure its radius, then compute its volume and multiply by density to get the mass.
d. Compute its spectroscopic parallax, then apply the mass-luminosity relation. ANSWER: d
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44. What is the most reliable way to measure the mass of a star for which the distance is
known? a. Apply the mass-luminosity relation.
b. Measure its orbit around another star.
c. Measure its radius, then compute its volume and multiply by density to get the mass.
d. Apply the mass-temperature relation.
ANSWER: b
45. To determine the orbital period of a visual binary, what must we measure? a. position
on the sky
b. brightness
c. luminosity
d. temperature
ANSWER: a
46. In a binary system, where will the more massive star be found? a. at the centre of mass
b. farthest from the centre of mass
c. nearest the centre of mass
d. following the largest orbit ANSWER: c
Binary
47. The diagram illustrates two stars in a visual binary system and the centre of mass of this
system. Based on this diagram, what is the ratio of the mass of star A to the mass of star B?
a. 2 to 1
b. 1 to 2
c. 2 to 3 d. 3 to 2
ANSWER: b
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48. Which of the following is a characteristic of an eclipsing binary? a. It will be more
luminous than a visual binary.
b. It will also be observed as a spectroscopic binary.
c. It will show a constant Doppler shift in its spectral lines.
d. It will show two stars with variable proper motion.
ANSWER: b
49. Why are spectroscopic binaries difficult to analyze? a. We can't see the shape or tilt of
the orbit.
b. We can't find the diameters of the stars.
c. We can't determine the luminosities of the stars. d. The Doppler shift is not measurable.
ANSWER: a
50. What does a spectroscopic binary show periodic variations in? a. brightness
b. proper motion c. radial velocity d. spectral type
ANSWER: c
51. You observe a spectroscopic binary star system. If you measure Doppler shifts in the
spectrum and determine that star A is blueshifted and star B is redshifted, what can you
conclude about the stars?
a. Star B is receding and star A is approaching.
b. Star B is approaching and star A is receding.
c. The stars are perpendicular to the line of sight. d. Star A is moving faster than star B.
ANSWER: a
52. An eclipsing binary has been analyzed and it has been determined that the ratio of the
mass of star A to the mass of star B is 6 : 1, and that the total mass of the two stars is 26
solar masses. What are the masses of star A and star B?
a. Star A has a mass of 1 solar mass and star B has a mass of 6 solar masses.
b. Star A has a mass of 20 solar masses and star B has a mass of 6 solar masses.
c. Star A has a mass of 22.3 solar masses and star B has a mass of 3.7 solar masses. d. Star A
has a mass of 31.2 solar masses and star B has a mass of 5.2 solar masses.
ANSWER: c
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53. Consider two binary star systems, A and B, in which the distance between the stars is
the same. If the total mass of the stars in system A is greater than the total mass of the stars
in system B, which of following can you conclude?
a. The primary in A is closer to the centre of mass than the primary in B.
b. The primary in A is farther from the centre of mass than the primary in B.
c. The orbital period of the stars in A is shorter than the orbital period of the stars in B. d.
The orbital period of the stars in A is longer than the orbital period of the stars in B.
ANSWER: d Radial
54. The diagram shows the radial velocity curve of a double-line spectroscopic binary.
Based on this radial velocity curve, what is the mass of star B compared to star A?
a. Star B is one-tenth the mass of star A.
b. Star B is half the mass of star A.
c. Star B is twice the mass of star A.
d. Star B is ten times the mass of star A.
ANSWER: c
55. If we can solve the orbital motion of a spectroscopic binary, what can we find? a. the
mass of each star
b. the diameter of each star
c. the orbital period
d. the sum of the stars’ masses ANSWER: d
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Curve
56. In the light curve shown in the diagram, what is the period of the eclipsing binary? a. 5
days
b. 32.5 days c. 42.5 days d. 50 days
ANSWER: b Cooler
57. At what point in the eclipsing binary light curve shown in the diagram is the cooler star
in front of the hotter star? a. 1
b. 2 c. 3 d. 4
ANSWER: d
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58. If the orbital velocity of an eclipsing binary is 97 km/sec and the smaller star is
completely eclipsed in 2 hours, what is the diameter of the smaller star?
a. 194 km
b. 4656 km
c. 350,000 km d. 700,000 km
ANSWER: d
59. Define the range of a property as the maximum value divided by the minimum value.
Which property of stars has the greatest range?
a. mass
b. radius
c. luminosity d. temperature
ANSWER: c
60. Which stars on the main sequence have the greatest mass?
a. the spectral type M stars
b. the spectral type O stars
c. the stars in the lower right of the Hertzsprung-Russell diagram d. the stars in the lower
left of the Hertzsprung-Russell diagram
ANSWER: b
61. Which of the following pieces of information are needed to calculate the total mass of a
binary system? a. the ratio of the angular separation from the centre of mass of each of the
stars
b. the semi-major axis and period of the orbit
c. the radial velocities of the two stars
d. the time required for the small star to eclipse the larger star
ANSWER: b
62. Based on the mass-luminosity relation, approximately what luminosity would a 2 solar
mass star on the main sequence have?
a. 0.5 solar luminosities
b. 2 solar luminosities
c. 4 solar luminosities d. 11 solar luminosities
ANSWER: d
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63. Which of the following kinds of stars best obey the mass-luminosity relation? a. main-
sequence stars
b. giant stars
c. supergiant stars
d. white dwarfs
ANSWER: a
64. Which one of the following kinds of stars is most dense? a. a supergiant star
b. a main-sequence star
c. a giant star
d. a white dwarf
ANSWER: d
65. Which star type in the Milky Way is likely to be most completely catalogued? a. red
main-sequence stars, because there are so many of them
b. luminous stars, because they are bright and easy to find
c. stars like the Sun, because the Sun is a typical star
d. white dwarf stars, because they are so old
ANSWER: b
66. What property do most of the (apparently) bright stars in the sky share? a. They are
close to Earth.
b. They are very luminous.
c. They are main-sequence stars.
d. They are red dwarfs.
ANSWER: b
67. What property do most of the nearest stars in the sky share? a. They have high
temperatures.
b. They are very luminous.
c. They are main-sequence stars.
d. They are red dwarfs. ANSWER: d
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68. What type of stars are the most common? a. supergiants
b. giants
c. upper (more luminous) main-sequence stars d. lower (less luminous) main-sequence
stars
ANSWER: d
69. If you took a random sample of 100 main-sequence stars in the Sun’s neighbourhood,
what would you expect their total mass to be?
a. Much less than 1 solar mass.
b. About 1 solar mass.
c. About 10 solar masses. d. About 100 solar masses.
ANSWER: c
70. The parallax of the star 75 Leo is 0.10 and its apparent visual magnitude is +5.18. The
absolute visual magnitude of 75 Leo is ____________________.
ANSWER: +5.18
71. Most stars on the Hertzsprung-Russell diagram are on the _______ ____________.
ANSWER: mainsequence
72. The largest of the red stars are the ____________________ stars.
ANSWER: supergiant
73. A G2 I star is ____________________ in diameter and ____________________ luminous than the
Sun.
ANSWER: Larger,more
74. ____________________ can be used to determine the distance to a star, when the spectrum of
the star can be used to determine its spectral type and luminosity class.
ANSWER: Spectroscopicparallax
75. Luminosity class IV objects are known as ____________________.
ANSWER: subgiants
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76. On the Hertzsprung-Russell diagram, indicate the location of the white dwarf stars.
ANSWER: Anelongatedregionshouldbeindicatedthatstretchesfromaluminosityofabout102
andspectral type B to luminosity of about 10-4 and spectral type G. (See Figure 6.8 in the
text.)
77. Look carefully at this diagram of a radial velocity curve for a spectroscopic binary.
Which of the stars is most massive? ____________________
ANSWER: StarB
78. The masses and diameters of each star in a binary can be determined from
____________________ binaries.
ANSWER: eclipsing
79. For stars on the main sequence, the luminosity can be estimated by the formula L =
____________________.
ANSWER: M3.5
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80. If we divide the mass of a star by its volume, we calculate the star's ____________________.
ANSWER: averagedensity
81. A star with a parallax of 0.02 seconds of arc is at a distance of 1000 parsecs. a. True
b. False
ANSWER: False
82. The absolute magnitude of a star is the apparent magnitude it would have if it were 33
light-years from Earth. a. True
b. False
ANSWER: True
83. The location of a star in the Hertzsprung-Russell diagram indicates its temperature and
intrinsic brightness. a. True
b. False
ANSWER: True
84. Absorption lines in the spectra of supergiant stars are broader than the same spectral
lines in main-sequence stars of the same spectral type.
a. True
b. False
ANSWER: False
85. Giant stars are members of luminosity class III. a. True
b. False
ANSWER: True
86. If a star is twice as hot as the Sun and only half the Sun's diameter, it will be less
luminous than the Sun. a. True
b. False
ANSWER: False
87. The method of spectroscopic parallax cannot be applied to stars more that about 300
light-years distant. a. True
b. False ANSWER: False
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88. The most common kinds of stars are low luminosity stars. a. True
b. False
ANSWER: True
89. Supergiants are about as common as the Sun. a. True
b. False
ANSWER: False
90. White dwarfs have such low luminosity that even the nearest white dwarfs are not
visible to the naked eye. a. True
b. False
ANSWER: True
91. To observe a visual binary, we must measure radial velocities. a. True
b. False
ANSWER: False
92. The more massive star in a binary system is always farthest from the centre of mass. a.
True
b. False
ANSWER: False
93. If a binary system has a period of 4 years and a separation of 5 AU, then the total mass is
7.8 solar masses. a. True
b. False
ANSWER: True
94. To observe a spectroscopic binary, we must be able to see both stars individually. a. True
b. False
ANSWER: False
95. We can find the masses and diameters of stars that are in eclipsing binary systems. a.
True
b. False ANSWER: True
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96. When we see a binary system producing eclipses, we know that the orbit is nearly edgeon. a. True
b. False
ANSWER: True
97. The most massive main-sequence stars are the M stars. a. True
b. False
ANSWER: False
98. The densest stars in the Hertzsprung-Russell diagram are the white dwarfs. a. True
b. False
ANSWER: True
99. An M star is hotter than an O star. a. True
b. False
ANSWER: False
100. On the Hertzsprung-Russell diagram, lines of constant radius slant downward from left
to right. a. True
b. False
ANSWER: True
101. The luminosity of a star is the total amount of energy it radiates each second. a. True
b. False
ANSWER: True
102. Why would parallaxes be easier to observe if the Earth were farther from the Sun?
ANSWER: Answernotprovided.
103. How does absolute visual magnitude tell us the intrinsic brightness of a star?
ANSWER: Answernotprovided.
104. How do absolute visual magnitude and luminosity differ?
ANSWER: Answernotprovided.
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105. How does a Hertzsprung-Russell diagram make it clear that giant stars are larger than
main-sequence stars of the same temperature?
ANSWER: Answernotprovided.
106. How does luminosity depend on temperature for stars of the same size?
ANSWER: Answernotprovided.
107. How can we be certain that white dwarfs are very small?
ANSWER: Answernotprovided.
108. How do the spectra of giants, supergiants, and main-sequence stars differ?
ANSWER: Answernotprovided.
109. How can we find the distance to a star that is too distant to have a measurable
parallax?
ANSWER: Answernotprovided.
110. What is the most common kind of star? What measurements must be made to discover
this information?
ANSWER: Answernotprovided.
111. Why is it difficult to decide how common hot stars are?
ANSWER: Answernotprovided.
112. Describe the measurements needed to determine the orbit of a visual binary star.
ANSWER: Answernotprovided.
113. What measurements are needed to determine the orbital motion of a spectroscopic
binary star?
ANSWER: Answernotprovided.
114. What information can we get from eclipsing binaries that we cannot get from visual
binaries?
ANSWER: Answernotprovided.
115. What information about orbital inclination can we get from visual binaries, from
spectroscopic binaries, and from eclipsing binaries?
ANSWER: Answernotprovided.
116. For what kinds of stars are the masses of stars in the Hertzsprung-Russell diagram
“orderly”? For what kinds of stars are they “disorderly”? In other words, could you guess
the mass of a star from its location (luminosity, temperature) on the Hertzsprung-Russell
diagram?
ANSWER: Answernotprovided.
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117. How does density divide the stars in the Hertzsprung-Russell diagram into three
groups? ANSWER: Answernotprovided.
118. Which are the most common stars, massive stars or low-mass stars (relative to the
Sun)? High luminosity or low luminosity (relative to the Sun)?
ANSWER: Answernotprovided.
119. Why is spectroscopy of binary stars such an important aspect of astronomy?
ANSWER: Answernotprovided.
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1. Which of the following relationships is the key to nuclear reactions in a star’s core
remaining under control? a. Luminosity depends on mass.
b. Pressure depends on temperature.
c. Density depends on mass.
d. Weight depends on temperature.
ANSWER: b
2. What is opacity?
a. the balance between the pressure and force of gravity inside a star
b. the force that binds protons and neutrons together to form a nucleus
c. the temperature and density at which a gas will undergo thermonuclear fusion d. a
measure of the resistance to the flow of radiation (photons) through a gas
ANSWER: d
3. What causes the outward gas pressure that balances the inward pull of gravity in a mainsequence star? a. the rapid outward flow of gas
b. the rapid inward flow of gas
c. the high temperature and density of the gas
d. the low mass of helium nuclei
ANSWER: c
4. Why is convection important in stars?
a. because it mixes the star’s gases and increases the temperature of the star
b. because it mixes the star’s gases and transports energy outwards
c. because it carries energy toward the core of the star
d. because it carries the neutrinos to the surface of the star where they can escape
ANSWER: b
5. How does the temperature inside a star determine how energy flows inside it? a. The
radiation rate depends on temperature.
b. The dependence of opacity on temperature makes convection happen.
c. The dependence of opacity on temperature makes conduction happen.
d. The temperature determines how much energy is produced at each layer. ANSWER: b
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6. Which of the following is the best example of energy transport by conduction? a. Your
feet are warmed when you hold them in front of a fire.
b. Your feet are warmed when you wear socks.
c. Your feet get cold when you stand on a cold floor.
d. Your feet get cold when you hold them over a cool air vent.
ANSWER: c
7. What does solving equations on a computer have to do with making a stellar model? a.
The equations apply the laws of stellar structure at locations within the star.
b. Equations can describe the H-R diagram and a star’s location on it.
c. The mass-luminosity equation tells you how to find a star’s luminosity given its mass. d.
Equations are used to model the nuclear reactions inside a star.
ANSWER: a
8. What does the strong force do?
a. It binds electrons to the nucleus in an atom.
b. It holds the Moon in orbit around the Earth.
c. It creates the magnetic field associated with sunspots.
d. It binds protons and neutrons together to form a nucleus.
ANSWER: d
9. What concept explains why both fusion and fission release energy? a. proton-proton
chain energy
b. Coulomb barrier energy
c. strong force energy
d. nuclear binding energy
ANSWER: d
10. What is the name of the process by which the Sun turns mass into energy? a. nuclear
fission
b. nuclear fusion
c. convection
d. radiation ANSWER: b
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11. While on the main sequence, what is a star’s primary energy source? a. nuclear fusion
b. nuclear fission
c. gravitational potential energy
d. magnetic fields
ANSWER: a
12. Why does the proton-proton chain need high temperatures?
a. High temperatures increase the ground state energy of the hydrogen atom.
b. High temperatures increase the velocity of the protons so they can overcome the
Coulomb barrier. c. High temperatures lower the density of the gas.
d. High temperatures allow the neutrinos to carry more energy away than the reaction
produces.
ANSWER: b
13. Why do nuclear fusion reactions only take place in the interior of a star (rather than at
the surface)? a. The magnetic fields are strongest there.
b. The temperature and density are highest in the centre.
c. The core is the only place where hydrogen is found.
d. The strong nuclear force is only active in the centres of stars.
ANSWER: b
14. What is produced in the proton-proton chain?
a. two hydrogen nuclei, a single helium nucleus, and energy in the form of visible light b.
four hydrogen nuclei and energy in the form of gamma rays
c. a helium nucleus and energy in the form of gamma rays
d. two hydrogen nuclei and energy in the form of visible light
ANSWER: c
15. What happens in the proton-proton chain?
a. Two protons are fused to make a helium nucleus. b. Three protons are fused to make a
lithium nucleus. c. A helium nucleus is split into four protons.
d. Four protons are fused to make a helium nucleus.
ANSWER: d
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16. What is the term for the process that fuses hydrogen into helium in the cores of massive
main-sequence stars? a. the CNO cycle
b. the proton-proton chain
c. hydrostatic equilibrium
d. the neutrino process
ANSWER: a
17. What happens in the carbon-nitrogen-oxygen (CNO) cycle?
a. Carbon nuclei are split 3 ways to make helium nuclei.
b. Carbon and oxygen combine to form nitrogen, which produces energy. c. Carbon and
nitrogen combine to form oxygen and energy.
d. Four hydrogen nuclei combine to form one helium nucleus and energy.
ANSWER: d
18. Stars with masses below a certain threshold produce most of their energy via the
proton-proton chain. What is that threshold?
a. 0.01 solar masses b. 0.1 solar masses c. 1.1 solar masses d. 11 solar masses
ANSWER: c
19. Which of the following is considered to be the best explanation for the missing solar
neutrinos? a. The Sun is fusing helium but not hydrogen.
b. Nuclear reactions do not produce neutrinos as fast as theory predicts.
c. The Sun may contain matter we haven't yet identified.
d. Neutrinos may oscillate between three different flavours.
ANSWER: d
20. How did observations at the Sudbury Neutrino Observatory solve the solar neutrino
problem? a. They showed that the “missing neutrinos” had changed into a different type.
b. They showed that other experiments had miscounted the number of solar neutrinos.
c. They showed that models for the number of neutrinos produced by the Sun were wrong.
d. They showed that neutrinos were not escaping from the core of the Sun. ANSWER: a
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21. Why does the main sequence have a limit at the lower end?
a. Low mass stars form from the interstellar medium very rarely.
b. Low mass objects are composed primarily of solids, not gases.
c. The lower limit represents a star with zero radius.
d. A minimum temperature is required for hydrogen nuclear fusion to take place.
ANSWER: d
22. Why is there a main sequence mass-luminosity relation?
a. because helium fusion produces carbon
b. because more massive stars support their larger weight by making more energy c.
because the helium flash occurs in degenerate matter
d. because all stars on the main sequence have about the same radius
ANSWER: b
23. What is the approximate mass of the lowest mass object that can initiate the
thermonuclear fusion of hydrogen? a. 0.08 solar mass
b. 1 solar mass
c. 8 solar masses
d. 80 solar masses
ANSWER: a
24. Which of the following is most similar in size to a brown dwarf? a. the planet Jupiter
b. a red dwarf
c. a white dwarf
d. a Bok globule
ANSWER: a
25. Which of the following are star-like objects that contain less than 0.08 solar masses and
will never raise their core temperatures high enough that the proton-proton chain can
begin?
a. brown dwarfs
b. Herbig-Haro objects
c. Bok globules d. T Tauri stars
ANSWER: a
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26. What would happen if the nuclear reactions in a star began to produce too much
energy? a. The star would shrink.
b. The star would expand.
c. The star would collapse.
d. Nothing would happen.
ANSWER: b
27. What would happen if the nuclear reactions in a star began to produce too little energy?
a. The star would expand.
b. The star would explode.
c. The star would contract.
d. Nothing would happen.
ANSWER: c
28. How much of its lifetime does the average star spend on the main sequence? a. 1%
b. 10% c. 20% d. 90%
ANSWER: d
29. The lower edge of the main-sequence band represents the location in the H-R diagram
at which stars begin their lives as main-sequence stars. What is it called?
a. the zero-age main sequence
b. the birth line
c. the Coulomb barrier d. the evolutionary track
ANSWER: a
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Main
30. On the H-R diagram, the line indicates the location of the main sequence. Which of the
four labelled locations on the H-R diagram indicates a luminosity and temperature similar
to that of a T Tauri star?
a. 1
b. 2
c. 3 d. 4
ANSWER: c
31. Refer to the H-R diagram. Which point represents a star in which the proton-proton
chain is occurring? a. 1
b. 2 c. 3 d. 4
ANSWER: c
32. Refer to the H-R diagram. Which point represents a star in which the CNO cycle is
occurring? a. 1
b. 2 c. 3 d. 4
ANSWER: a
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33. The Sun has an expected main-sequence lifetime of about 1010 years. What is the
lifetime on the main sequence of a 2 solar mass star?
a. 1.8×106 years b. 1.8×109 years c. 1.8×1010 years d. 1.8×1011 years
ANSWER: b
34. What type of star is our Sun? a. intermediate-mass star
b. yellow giant
c. low-mass star
d. high-mass star
ANSWER: c
35. What is the lifetime of a 10 solar mass star on the main sequence? a. 3.2×107 years
b. 1×109 years
c. 1×1011 years
d. 3.2×1012 years
ANSWER: a
36. Which of the following statements is true?
a. Low mass stars consume fuel rapidly.
b. Massive stars consume fuel rapidly.
c. Red giants are hotter than very massive stars. d. White dwarfs are readily visible by
naked eye.
ANSWER: b
37. What characteristic of a star primarily determines its location on the main sequence? a.
age
b. distance from the galactic centre c. mass
d. radius
ANSWER: c
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38. In which option below are the stellar types sorted from shortest to longest mainsequence lifetime? a. O, A, K, M
b. A, B, F, G c. K, F, B, O d. B, A, M, G
ANSWER: a
39. Consider two stars of the same mass: star 1 has just moved on to the main sequence,
and star 2 is about to leave it. How are these two stars different?
a. Star 2 has more helium in its core and a hotter surface.
b. Star 2 has more helium in its core and a cooler surface.
c. Star 1 is more luminous and has a hotter surface. d. Star 1 is more luminous and has a
cooler surface.
ANSWER: b
40. Why do higher mass stars live shorter lives on the main sequence than lower mass
stars? a. Higher mass stars burn through their nuclear fuel faster.
b. Lower mass stars don't get their energy from nuclear fusion like higher mass stars do. c.
Higher mass stars have less hydrogen fuel to burn.
d. Lower mass stars spend a longer time evolving to the main sequence.
ANSWER: a
41. What causes the dimming of starlight in the interstellar medium? a. dust particles
b. ionized hydrogen
c. neutral hydrogen
d. molecular gas
ANSWER: a
42. Due to the dust in the interstellar medium, how will a distant star appear to an observer
on Earth? a. brighter and cooler than it really is
b. brighter and hotter than it really is
c. fainter and cooler than it really is
d. fainter and hotter than it really is ANSWER: c
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43. Which of the following factors explain why infrared telescopes are used to observe
protostars? a. density and composition
b. density and the presence of dust
c. temperature and the presence of dust
d. temperature and luminosity
ANSWER: c
44. Absorption lines due to the interstellar medium indicate that some components of the
interstellar medium are cold and of a very low density. How do they show this?
a. The lines are blue shifted.
b. The lines are red shifted.
c. The lines are extremely broad. d. The lines are extremely narrow.
ANSWER: d
45. How do absorption lines from interstellar gas compare to absorption lines from stars?
a. They are wider than the lines from stars because the gas is hotter than most stars.
b. They are narrower than the lines from stars because the gas has a lower pressure than
stars. c. They indicate that the interstellar medium contains different elements than stars
do.
d. They indicate that interstellar medium clouds have high velocities.
ANSWER: b
46. What evidence can be used to show that space is not a vacuum? a. ultraviolet radiation
emitted by dust
b. narrow emission lines seen in stellar spectra
c. the presence of bright nebulae
d. the blue colour of stars seen near dark regions
ANSWER: c
47. Where are stars born?
a. reflection nebulae
b. dense molecular clouds c. HII regions
d. the intercloud medium
ANSWER: b
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48. What would an H-R diagram of a young star cluster show?
a. high mass stars that have not reached the main sequence yet b. low mass stars that have
not reached the main sequence yet
c. mainly giant stars, since most stars have left the main sequence d. no stars, since none
have reached the main sequence yet
ANSWER: b
49. Which of the following telescopes would be most suitable for observing molecular
clouds? a. ultraviolet telescope
b. visible light telescope
c. gamma ray telescope
d. radio telescope
ANSWER: d
50. How can molecular clouds be observed?
a. by using infrared telescopes to detect ionized gas in the clouds
b. by using X-ray telescopes to observe the X-ray radiation from the molecules in the cloud
c. by using radio telescopes to observe the emission from CO molecules in the clouds
d. by using radio telescopes to observe the 21-cm radiation from hydrogen
ANSWER: c
51. Because they are composed of ionized hydrogen, emission nebulae have another name
— what is that name? a. HI regions
b. HII regions c. Bok globules d. HeI regions
ANSWER: b
52. Why are emission nebulae associated with young stars?
a. Young stars have not moved far from the gaseous nebulae where they were born. b. Only
hot stars can ionize nearby gas; hot stars are high-mass, so must be young. c. The dust that
makes emission nebulae glow is destroyed by old stars.
d. Young stars produce the blue light that is scattered by emission nebulae.
ANSWER: b
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53. What can initiate the free-fall contraction of a molecular cloud? a. shock waves from
supernovae
b. nearby spectral type G stars
c. the rotation of the cloud
d. the cloud becoming transparent to ultraviolet radiation
ANSWER: a
54. Under what conditions might interstellar gas clouds collapse to form stars? a. if they
encounter a shock wave
b. if they have very high temperatures
c. if they rotate rapidly
d. if they are located near main-sequence spectral type K and M stars
ANSWER: a
55. The formation of one of the following phenomena requires that a young hot star (T =
25,000 K) be relatively close by. Which one?
a. emission nebulae
b. HI regions
c. molecular clouds
d. 21-centimetre radiation
ANSWER: a
56. What happens to light as it passes through dark nebulae? a. transmission
b. emission c. reflection d. absorption
ANSWER: d
57. What force is responsible for the collapse of an interstellar cloud? a. gravity
b. nuclear c. electric d. magnetic
ANSWER: a
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58. Star clusters are important to the study of stellar evolution because all the stars in a
given cluster have one thing in common. What is it?
a. temperature
b. mass
c. age
d. luminosity
ANSWER: c
59. What is the term for a group of 10 to 100 stars that formed at the same time but are so
widely scattered in space that their mutual gravity cannot hold them together?
a. a globular cluster
b. an open cluster
c. an association
d. a spherical component
ANSWER: c
60. As a human with a temperature of about 310 K, you radiate most strongly at a
wavelength of about 10 micrometres. If the dust around a protostar radiates most strongly
at 30 micrometres, what is the approximate temperature of that dust?
a. 100,000 K
b. 10,000 K c. 1000 K d. 100 K
ANSWER: d
61. What does the time a protostar takes to contract from a cool interstellar gas cloud to a
main-sequence star mainly depend on?
a. luminosity
b. mass
c. magnetic field
d. location on the main sequence
ANSWER: b
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62. As a star begins to form, what is its primary energy source? a. nuclear fusion
b. nuclear fission
c. gravitational potential energy
d. magnetic fields
ANSWER: c
63. Which of the following are small dark nebulae about 1 light-year in diameter, with
masses from 10 to 1,000 solar masses?
a. HII regions
b. emission nebulae c. Bok globules
d. reflection nebulae
ANSWER: c
64. What occurs when some of the material collapsing to form a protostar is ejected from its
poles? a. A protoplanetary disk forms.
b. The star stops collapsing.
c. The T Tauri phenomenon occurs.
d. Jets extend into the interstellar medium.
ANSWER: d
65. What must occur for an object to be considered a main-sequence star? a. Hydrostatic
equilibrium ends.
b. Nuclear fusion reactions in the core begin.
c. Helium flash occurs in the core.
d. Gravitational contraction begins.
ANSWER: b
66. Why are protostars difficult to observe?
a. The protostar stage is very long.
b. They are all so far away that the light hasn't reached us yet. c. Most of their radiation is in
the form of X-rays.
d. They are surrounded by cocoons of gas and dust.
ANSWER: d
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67. Upon observing a nebula, you discover that many stars are surrounded by disks of gas
and dust. What can you conclude about these stars?
a. They are very young.
b. They are very old.
c. They are red giants.
d. They are white dwarfs.
ANSWER: a
68. Which of the following are small luminous nebulae excited by young stars nearby? a. T
Tauri stars
b. Bok globules
c. O associations
d. Herbig-Haro objects
ANSWER: d
69. Why is the presence of massive stars in the Orion Nebula an indication that star
formation is currently occurring? a. The Orion Nebula contains large amounts of gas and
dust.
b. Massive stars have short lives, so they must have formed recently.
c. Massive stars trigger star formation in nearby gas clouds.
d. The Orion Nebula contains large numbers of brown dwarfs and supernova remnants.
ANSWER: b
70. What is the source of the pink glow within the Great Nebula in Orion? a. a Herbig-Haro
object
b. a reflection nebula made of dust
c. young low-mass stars
d. an emission nebula made of gas
ANSWER: d
71. ____________________ is the resistance of a gas to the flow of radiation.
ANSWER: Opacity
72. The condition of ____________________ means that the force due to gravity pushing
downward on a layer is exactly equal to the pressure pushing upward on that layer.
ANSWER: hydrostaticequilibrium
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73. The pressure of an interstellar gas cloud depends on the cloud’s ____________________ and
____________________.
ANSWER: temperature,density density, temperature
74. When energy is carried by the bulk motion of matter, that is called ____________________.
ANSWER: convection
75. Energy transport by ____________________ is important when photons cannot readily travel
through a gas. ANSWER: convection
76. Stars with masses greater than 1.1 solar masses use the ____________________ to convert
hydrogen into helium and produce energy
ANSWER: CNOcycle
77. A(n) ____________________ is a subatomic particle produced in nuclear fusion that can travel
through the Sun and escape to space without interacting with any particles in the Sun.
ANSWER: neutrino
78. A star on the _________ ________________ generates enough energy from nuclear fusion to
halt gravitational collapse.
ANSWER: mainsequence
79. ____________________ appear reddish or pink in colour due to the light emitted by the
Balmer series of the hydrogen atom.
ANSWER: Emissionnebulae HII regions
80. A(n) ____________________ is a cool, dense cloud of dust and gas that is undergoing
gravitational contraction. ANSWER: protostar
81. Some young star clusters contain large numbers of T Tauri stars. a. True
b. False ANSWER: True
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82. Ninety percent of all stars fuse helium to form carbon and lie on the main sequence. a.
True
b. False
ANSWER: False
83. Nuclear fusion in stars is controlled by the dependence of density on mass. a. True
b. False
ANSWER: False
84. The Sun has a core in which energy travels outward primarily by radiation. a. True
b. False
ANSWER: True
85. The Sun makes most of its energy by the CNO cycle. a. True
b. False
ANSWER: False
86. Energy flows by radiation or convection inside stars but almost never by conduction. a.
True
b. False
ANSWER: True
87. Hydrostatic equilibrium refers to the balance between weight and pressure. a. True
b. False
ANSWER: True
88. The Orion region contains young main-sequence stars and an emission nebula, but the
original molecular cloud they formed out of has been dispersed.
a. True
b. False
ANSWER: False
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89. T Tauri stars are believed to be young, high mass, main-sequence stars. a. True
b. False
ANSWER: False
90. The dust in the interstellar medium can make distant stars look redder than they really
are. a. True
b. False
ANSWER: True
91. Bok globules are small, dark fragments of the interstellar medium. a. True
b. False
ANSWER: True
92. The thermal motions of the atoms in a gas cloud can make it collapse to form a
protostar. a. True
b. False
ANSWER: False
93. Molecular clouds are mapped using CO instead of hydrogen because CO is much more
abundant than hydrogen in molecular clouds.
a. True
b. False
ANSWER: False
94. HII regions are found near stars cooler than 25,000 K because large amounts of
ultraviolet photons would totally destroy the hydrogen atoms in the gas.
a. True
b. False
ANSWER: False
95. The pressure of a gas depends on the temperature and density of the gas. a. True
b. False ANSWER: True
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96. Some massive stars only live a few million years. a. True
b. False
ANSWER: True
97. In an H-R diagram, pre–main-sequence stars are above and to the right of the main
sequence. a. True
b. False
ANSWER: True
98. Higher mass stars evolve more slowly to the main sequence than lower mass stars. a.
True
b. False
ANSWER: False
99. Stars of one solar mass produce their energy by the set of nuclear reactions called the
CNO cycle. a. True
b. False
ANSWER: False
100. The nucleus of the hydrogen atom consists of a single neutron. a. True
b. False
ANSWER: False
101. Stars of spectral type K have strong Balmer lines. a. True
b. False
ANSWER: False
102. The solar neutrino experiments detected about twice as many neutrinos as theory
predicted should be detected. a. True
b. False
ANSWER: False
103. How does a gas cloud become hot enough to ignite nuclear reactions?
ANSWER: Answernotprovided.
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104. What observations confirm the existence of protostars? ANSWER: Answernotprovided.
105. Why do nuclear reactions in a star occur only near its centre? ANSWER:
Answernotprovided.
106. What is the difference between the proton-proton chain and the CNO cycle? ANSWER:
Answernotprovided.
107. Explain what keeps the nuclear reactions in a star under control. ANSWER:
Answernotprovided.
108. How does the method of energy generation inside main-sequence stars affect their
internal structure? ANSWER: Answernotprovided.
109. What observations reveal star formation in the Orion nebula? ANSWER:
Answernotprovided.
110. What observations demonstrate the existence of an interstellar medium? ANSWER:
Answernotprovided.
111. Why are interstellar absorption lines so narrow compared to the width of lines that
originate in the photospheres of stars?
ANSWER: Answernotprovided.
112. Why are reflection nebulae blue in colour?
ANSWER: Answernotprovided.
113. What observations indicate the presence of dust in the interstellar medium?
ANSWER: Answernotprovided.
114. Why do astronomers use the molecule CO to map molecular clouds, instead of
hydrogen?
ANSWER: Answernotprovided.
115. Why are distant stars redder than nearby stars of the same spectral type?
ANSWER: Answernotprovided.
116. Why are massive stars more luminous than low mass stars? That is, why is there a
mass-luminosity relation?
ANSWER: Answernotprovided.
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117. Why is there a lower end to the main sequence? Why is there an upper end to the main
sequence? ANSWER: Answernotprovided.
118. How do measurements of neutrinos from the Sun pose a problem for modern
astronomy? ANSWER: Answernotprovided.
119. What is the role of shock waves in star formation? ANSWER: Answernotprovided.
120. List the three kind of nebulae. Describe each. ANSWER: Answernotprovided.
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1. As a star exhausts the hydrogen in its core, what happens? a. It becomes hotter and more
luminous.
b. It becomes hotter and less luminous.
c. It becomes cooler and less luminous.
d. It becomes cooler and more luminous.
ANSWER: d
2. When does a star experience helium fusion? a. just before it enters the main sequence
b. after it has become a red giant star
c. when it is on the horizontal branch
d. before it leaves the main sequence
ANSWER: c
3. Why are giant and supergiant stars rare?
a. The giant and supergiant stages are very short.
b. The star blows up before the giant or supergiant stage is reached. c. They do not form as
often as main sequence stars.
d. The giant or supergiant stage is very long.
ANSWER: a
4. Which of the following statements best describes why stars eventually die? a. Their
lifespan is limited.
b. They exhaust all their fuel.
c. Their cores become hotter.
d. They become less luminous.
ANSWER: b
5. Which of the following occurs during the giant stage?
a. helium fusion in the core and hydrogen fusion in the surrounding shell b. hydrogen fusion
in the core and helium fusion in the surrounding shell c. hydrogen and helium fusion in the
core
d. hydrogen flash
ANSWER: a
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6. In what way are giants and supergiants similar?
a. They are the main sequence stars.
b. They undergo a helium flash stage as they enter the main sequence. c. They are very
luminous.
d. Their cores expand rapidly to reach giant sizes.
ANSWER: c
7. What do we call the region of the HR diagram that represents giant stars that are fusing
helium in their cores and then in their shells?
a. turnoff point
b. horizontal branch
c. turn-on point d. main sequence
ANSWER: b
8. Why are star clusters important to our study of stars?
a. because all stars formed in star clusters
b. because they allow us to test our theories and models of stellar evolution c. because the
Sun was once a member of a globular cluster
d. because they are the only objects that contain Cepheid variables
ANSWER: b
9. What property is the same for all stars in a star cluster? a. age
b. mass
c. luminosity d. radius
ANSWER: a
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10. Which point indicates the location on the H-R diagram of a one-solar-mass star when it
stars to fuse helium?
a. 1 b. 2 c. 3 d. 4
ANSWER: d
11. Why can’t the lowest mass stars become giants? a. Their centres never get hot enough.
b. Their rotation is too slow.
c. They do not contain helium.
d. They never use up their hydrogen.
ANSWER: a
12. How is a giant star different from the star it evolved from? a. A giant is hotter and more
luminous.
b. A giant is hotter and less luminous.
c. A giant is cooler and more luminous.
d. A giant is cooler and less luminous.
ANSWER: c
13. After they leave the main sequence, what happens to stars with masses between 0.4 and
4 solar masses? a. They undergo thermonuclear fusion of hydrogen and helium, but never
get hot enough to ignite carbon. b. They undergo thermonuclear fusion of hydrogen, but
never get hot enough to ignite helium.
c. They produce type-I supernovae after they exhaust their nuclear fuels.
d. They produce type-II supernovae after they exhaust their nuclear fuels. ANSWER: a
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14. About how long will a 0.5 solar mass star spend on the main sequence? a. 5 million years
b. 570 million years
c. 5 billion years
d. 57 billion years
ANSWER: d
15. For a star with a mass similar to that of the Sun, what is the last stage of the nuclear
fusion? a. hydrogen to helium
b. helium to carbon and oxygen
c. carbon to magnesium
d. silicon to iron
ANSWER: b
16. A low mass star goes through several stages of life from birth to death. Which of the
following lists are in correct order?
a. protostar, main sequence star, red giant, supernova, neutron star
b. protostar, main sequence star, planetary nebula, super giant, supernova c. protostar,
main sequence star, red giant, planetary nebula, white dwarf d. protostar, main sequence
star, white dwarf, red giant
ANSWER: c
17. What happens to stars that have ejected a planetary nebula? a. They become protostars.
b. They become brown dwarfs.
c. They become white dwarfs.
d. They become red giants.
ANSWER: c
18. After what evolutionary stage does a star become a white dwarf? a. protostar
b. pre-main sequence c. main sequence
d. giant
ANSWER: d
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19. What is a planetary nebula?
a. the expelled outer envelope of a medium mass star
b. a cloud of hot gas produced by a supernova explosion c. a nebula within which planets
are forming
d. a cloud of hot gas surrounding a planet
ANSWER: a
20. What does a planetary nebula do? a. produces an absorption spectrum b. produces an
emission spectrum c. contracts to form planets
d. contracts to form a star
ANSWER: b
21. What is the term for a collection of 100 to 1000 young stars in a region about 80 lightyears in diameter? a. Herbig-Haro object
b. globular cluster
c. open cluster
d. giant cluster ANSWER: c
22. What is the term for a collection of 105 to 106 old stars in a region 30 to 100 light-years
in diameter? a. Herbig-Haro object
b. globular cluster
c. open cluster
d. giant cluster
ANSWER: b
23. What is the defining characteristic of stars within a cluster that are at the turnoff point?
a. They are just leaving the main sequence.
b. They are just becoming white dwarfs.
c. They are just entering the main sequence.
d. They are about to explode in supernovae. ANSWER: a
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Cluster
24. What is the approximate age of the star cluster in the H-R diagram? (Hint: Main
sequence stars of spectral types O and B have a core supply of hydrogen that is sufficient to
last about 250 million years; types A and F, about 2 billion years; type G about 10 billion
years; types K and M about 30 billion years. The apparent magnitude scale means that
larger numbers are toward the bottom of the vertical axis.)
a. 200 million years b. 2 billion years
c. 10 billion years d. 30 billion years
ANSWER: c
25. Refer to the H-R diagram. What type of star do the two data points above spectral type
“A” represent? a. massive main sequence stars
b. massive supergiant stars
c. white dwarfs with mass less than the sun’s mass
d. white dwarfs with mass greater than twice the sun’s mass
ANSWER: c
26. Refer to the H-R diagram. What type of star do the data points above spectral type “M”
represent? a. massive main sequence stars
b. main sequence stars with mass less than the sun’s mass
c. main sequence stars with luminosities higher than the sun’s luminosity
d. pre-main sequence stars ANSWER: b
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27. Refer to the H-R diagram. How would the H-R diagram of an older star cluster look
different?
a. The points would shift to the right, because all of the stars would have lower
temperatures.
b. The lower main sequence would look the same, but the turnoff would be at spectral type
K or M. c. The points would shift down, because all of the stars would have lower
luminosities.
d. The lower main sequence would look the same, but the turnoff would be at spectral type
F or A.
ANSWER: b
28. Refer to the H-R diagram. How would the H-R diagram of a more distant star cluster
look different? a. The points would shift down, because all of the stars would have larger
apparent magnitudes.
b. The points would shift to the right, because all of the stars would appear to be cooler.
c. The points would shift up, because all of the stars would have smaller apparent
magnitudes.
d. The points would shift to the left, because all of the stars would appear to be hotter.
ANSWER: a
29. Which nuclear fuels does a one solar mass star use over the course of its entire lifespan?
a. hydrogen
b. hydrogen and helium
c. hydrogen, helium, and carbon
d. hydrogen, helium, carbon, and oxygen
ANSWER: b
30. Star A is a 1 solar mass white dwarf, and star B is a 1.3 solar mass white dwarf. How
would they differ? a. Star A has a smaller radius.
b. Star B has a smaller radius.
c. Star B is supported by neutron degeneracy pressure.
d. Star A is hotter.
ANSWER: b
31. What is the source of the energy radiated by a white dwarf? a. the proton-proton chain
b. the CNO cycle
c. gravitational contraction after becoming a white dwarf
d. gravitational contraction during the white dwarf formation phase ANSWER: d
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32. What does the Chandrasekhar-Landau limit tell us?
a. Accretion disks can grow hot through friction.
b. Neutron stars of more than 3 solar masses are not stable.
c. White dwarfs more massive than 1.4 solar masses are not stable.
d. Stars with a mass less than 0.5 solar masses will not go through helium flash.
ANSWER: c
33. What is the ultimate fate of our Sun? a. It will become a neutron star.
b. It will explode in a supernova.
c. It will become a white dwarf.
d. It will explode in a nova.
ANSWER: c
34. Which scenario is most likely to happen when the Sun enters the red giant stage?
a. Mercury, Venus, and Earth will be destroyed by the expanding Sun.
b. Mercury will be destroyed by the expanding Sun, but Venus and Earth will remain intact.
c. The Sun will engulf and destroy all planets in the Solar System.
d. The Sun will never expand far enough to reach Mercury or any other planets in the Soar
System.
ANSWER: a
35. If the stars at the turnoff point of a cluster have a mass of 3 times the mass of the Sun,
what is the age of the cluster?
a. 6.4×108 years b. 3.3×109 years c. 3.0×1010 years d. 1.6×1011 years
ANSWER: a
36. Which of the following correctly describes a relationship between pressure,
temperature, and density in degenerate matter?
a. Pressure depends only on the temperature.
b. Pressure does not depend on temperature.
c. Temperature depends only on density. d. Pressure does not depend on density.
ANSWER: b
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37. What is a white dwarf composed of?
a. hydrogen nuclei and degenerate electrons
b. helium nuclei and normal electrons
c. carbon and oxygen nuclei and degenerate electrons d. degenerate iron nuclei
ANSWER: c
38. As a white dwarf cools, its radius remains the same. Why is this?
a. because pressure due to nuclear reactions in a shell just below the surface keeps it from
collapsing
b. because pressure does not depend on temperature for a white dwarf, since the electrons
are degenerate c. because pressure does not depend on temperature, since the star has
exhausted all its nuclear fuels
d. because material accreting onto it from a companion maintains a constant radius
ANSWER: b
39. What are the two longest stages in the life of a one solar mass star? a. protostar, pre–
main sequence
b. protostar, white dwarf
c. protostar, main sequence
d. main sequence, white dwarf
ANSWER: d
40. Which of the following is the most important factor that determines a life cycle of a star
(for example, why some stars have a short life span)?
a. mass
b. temperature
c. luminosity d. radius
ANSWER: a
41. What principle explains why matter flowing from one star in a binary system to its
companion forms an accretion disk?
a. conservation of tidal forces
b. conservation of temperature
c. conservation of angular momentum d. conservation of energy
ANSWER: c
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42. Suppose you discover a binary star system with a 0.7 solar mass giant star and a 2 solar
mass main sequence star. Why is this surprising?
a. 0.7 solar mass stars are not expected to become giants.
b. All 2 solar mass stars should have left the main sequence.
c. Giant stars are expected to destroy their companions, so the 2 solar mass star shouldn’t
exist. d. The 2 solar mass star should have become a giant before the 0.7 solar mass star.
ANSWER: d
43. When material expanding away from a star in a binary system reaches the edge of its
Roche lobe, what happens? a. The material will start to fall back toward the star.
b. All of the material will accrete on to the companion.
c. The material will no longer be gravitationally bound to the star.
d. The material will increase in temperature and eventually undergo thermonuclear fusion.
ANSWER: c
44. When mass is transferred toward a white dwarf in a binary system, the material forms a
rapidly growing whirlpool of material. What is that whirlpool called?
a. an accretion disk
b. an Algol paradox
c. a planetary nebula
d. a supernova remnant
ANSWER: a
45. Under what conditions are Type Ia supernovae believed to occur? a. when the core of a
massive star collapses
b. when a white dwarf exceeds the Chandrasekhar-Landau limit c. when hydrogen
detonation occurs
d. when neutrinos in a massive star form a shock wave that explodes the star
ANSWER: b
46. Which of the following is almost always associated with a nova? a. a very massive star
b. a star undergoing helium burning
c. a white dwarf in a close binary system
d. a solar-like star that has exhausted its hydrogen and helium ANSWER: d
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47. Why can’t massive stars generate energy through iron fusion?
a. because iron fusion requires very high density
b. because no star can get hot enough for iron fusion
c. because both fusion and fission of iron nuclei absorb energy
d. because massive stars go supernova before they create an iron core
ANSWER: c
48. If the hypothesis that novae occur in close binary systems is correct, then which of the
following should novae do? a. They should produce synchrotron radiation.
b. They should occur in regions of star formation.
c. They should all be visual binaries.
d. They should repeat after some interval.
ANSWER: d
49. Why is the material that accretes onto a neutron star or black hole expected to emit Xrays? a. The material contains magnetic fields that will produce synchrotron radiation.
b. Hydrogen nuclei begin to fuse and emit high energy photons.
c. The material will become hot enough that it will radiate most strongly at X-ray
wavelengths. d. As the material slows down it converts thermal energy to gravitational
potential energy.
ANSWER: c
50. What is the term for the form of electromagnetic radiation produced by rapidly moving
electrons spiralling through magnetic fields?
a. Lagrangian radiation
b. ultraviolet radiation
c. synchrotron radiation d. infrared radiation
ANSWER: c
51. What type of object is the Crab nebula? a. a planetary nebula
b. an open cluster
c. an absorption nebula
d. a supernova remnant ANSWER: d
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52. In the year 1054 CE, Chinese astronomers observed the appearance of a new star. What
occupies that location now?
a. a molecular cloud
b. a planetary nebula with a white dwarf in the centre c. a supernova remnant with a pulsar
in the centre
d. nothing
ANSWER: c
53. What produces synchrotron radiation?
a. objects with temperatures below 10,000 K
b. high-velocity electrons moving through a magnetic field c. cold hydrogen atoms in space
d. helium burning in a massive star
ANSWER: b
54. Where is synchrotron radiation produced?
a. in planetary nebulae
b. in the outer layers of red dwarfs
c. in the collapsing iron cores of massive stars d. in supernova remnants
ANSWER: d
55. What does the explosion of a type II supernova typically leave behind?
a. It leaves behind a planetary nebula.
b. It leaves behind a shell of hot, expanding gas with a white dwarf at the centre. c. It leaves
behind a shell of hot, expanding gas with a pulsar at the centre.
d. Nothing is ever left behind.
ANSWER: c
56. Which of the following offered support for the theory that the collapse of a massive
star’s iron core produces neutrinos?
a. the detection of neutrinos from the supernova of 1987
b. the brightening of supernovae a few days after they are first visible c. underground
counts of solar neutrinos
d. laboratory measurements of the mass of the neutrino
ANSWER: a
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57. If you were to land on a neutron star, how would your mass change compared to your
mass on the Earth? a. It would increase a lot.
b. It would decrease a lot.
c. It would increase a little.
d. It would remain the same.
ANSWER: d
58. If you were to land on a neutron star, how would your weight change relative to your
weight on the Earth? a. It would increase a lot.
b. It would decrease a lot.
c. It would increase a little.
d. It would remain the same.
ANSWER: a
59. As an astronomer, you observe the night sky on a regular basis. One night, you notice a
new, bright star visible with the naked eye. Within the next two years, the new star
vanishes from sight. Which of the following best describes the object you observed?
a. a super bright planetary nebula
b. a white dwarf explosion c. a supernova explosion d. a red giant explosion
ANSWER: c
60. When does a type-II supernova occur?
a. when a white dwarf's mass exceeds the Chandrasekhar-Landau limit b. when the iron
core of a massive star collapses
c. directly following a helium flash
d. when two neutron stars collide
ANSWER: b
61. Which of the following has a radius of about 10 kilometres and is supported by the
pressure associated with degenerate neutrons?
a. black hole
b. neutron star
c. white dwarf
d. supernova remnant
ANSWER: b
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Super
62. The diagram shows a light curve from a supernova. How many days after maximum
light did it take for the supernova to decrease in brightness by 5 magnitudes?
a. less than 50
b. 50
c. 150 d. 250
ANSWER: c
63. The diagram shows a light curve from a supernova. About how long did it take for the
supernova to reach its maximum luminosity?
a. 25 days
b. 50 days
c. 100 days d. 200 days
ANSWER: a
64. Although neutron stars are very hot, they are faint and not easy to see at visual
wavelengths. Why is this? a. Light does not escape from their event horizon.
b. Most neutron stars lie beyond dense dust clouds.
c. They have only a small surface area from which to emit light.
d. The peak of their thermal emission is at infrared wavelengths. ANSWER: c
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65. Which of the following is a property of pulsars? a. pulsating gravitational field
b. rapid rotation
c. radius of at least 100 km
d. association with white dwarfs
ANSWER: b
66. What has greater density than a white dwarf? a. a neutron star
b. a red dwarf
c. a brown dwarf
d. a red giant
ANSWER: a
67. Why are neutron stars expected to spin rapidly?
a. They conserve angular momentum when they collapse.
b. They have high orbital velocities.
c. They have high densities.
d. The energy from the supernova explosion that formed them makes them spin faster.
ANSWER: a
68. Do all supernova remnants contain pulsars?
1. Yes, pulsars are visible in all supernova remnants.
2. No, some supernova explosions form white dwarfs instead of the neutron stars
necessary for pulsars.
3. No: all supernova remnants start out having pulsars but the pulsars can disappear
before the supernova remnant dissipates.
4. Yes, but some pulsars’ pulses are not visible from Earth because of the direction of
their rotational axis.
ANSWER: d
69. Why can’t pulsars be spinning white dwarfs?
a. White dwarfs are not very common.
b. White dwarfs are not dense enough to produce bright pulses. c. White dwarfs do not have
magnetic fields.
d. White dwarfs are too large to produce such short pulses.
ANSWER: d
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70. Who discovered the first pulsar, in November of 1967? a. Jocelyn Bell
b. Russell Hulse and Joseph Taylor c. Walter Baade
d. Edwin Hubble
ANSWER: a
71. Why is the name pulsar a poor description of the object? a. Pulsars are neutron stars.
b. Pulsars’ radio emissions are irregular.
c. Pulsars vibrate rather than pulsate.
d. Pulsars flash rather than pulsate.
ANSWER: d
72. Which of the following are neutron stars that have magnetic fields 100 times stronger
than the average neutron star?
a. hypernovae b. collapsars c. pulsars
d. magnetars
ANSWER: d
73. The rotation speed of pulsars slows down over time. What is believed to be the reason
for this? a. They are losing angular momentum into space via outward streaming particles.
b. They are dragging companion stars around in their magnetic fields.
c. They are conserving angular momentum.
d. Their mass is increasing.
ANSWER: a
74. Does the rotation speed of pulsars slow down over time?
a. No, the conservation of momentum does not permit that.
b. No, their energy is constantly replenished through magnetic fields.
c. Yes, they are losing angular momentum into space via outward streaming particles. d.
Yes, their density is decreasing over time.
ANSWER: c
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75. If you had an extremely sensitive radio telescope, could you detect every pulsar in the
Milky Way galaxy? a. Yes, because all pulsars emit radio waves.
b. Yes, because all pulsars are nearby.
c. No, some pulsars don’t flash all of the time.
d. No, some pulsar beams don’t point in the direction of Earth.
ANSWER: d
76. What is interesting about the orbit of the binary pulsar, PSR 1936+16, studied by Taylor
and Hulse? a. It is so small that the orbital period is smaller than the pulsar period.
b. It is growing smaller, presumably by emitting gravitational waves.
c. It provides evidence that it is being orbited by at least 6 planets the size of Jupiter.
d. It shows large changes each time an X-ray burst is emitted from the system.
ANSWER: b
77. How are millisecond pulsars unusual compared to other pulsars? a. Their spin rates are
fast for their age.
b. They only emit millimetre-wave radiation.
c. They have strong magnetic fields.
d. They are all X-ray binaries.
ANSWER: a
78. What is odd about the existence of planets around PSR J1257+12?
a. The gravitational pull of the pulsar should have pulled the planets down onto it.
b. Planets would not be expected to survive the supernova explosion that created the
pulsar. c. The planets should have been destroyed by the radiation from the pulsar.
d. The pulsar is rotating so fast that the planets should have been flung into space.
ANSWER: b
79. Where is the singularity of a black hole found?
a. It is found outside the event horizon.
b. It is located within the event horizon.
c. It is located at the Lagrangian point if the black hole is in a binary system. d. It doesn't
exist, since all black holes have a finite size.
ANSWER: b
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80. Which of the following factors does the escape velocity from the surface of an object
depend on? a. the object’s mass and radius
b. the object’s mass only
c. the object’s radius and the mass of the object trying to escape
d. the object’s radius and the speed of light
ANSWER: a
81. You are asked to calculate the escape velocity for a white dwarf. What information do
you need in order to complete your calculation?
a. the object’s orbital velocity
b. the object’s mass only
c. the object’s distance from the Earth d. the object’s mass and radius
ANSWER: d
82. What is the Schwarzschild radius?
a. the distance between a neutron star’s centre and its surface
b. the distance between a black hole and its event horizon
c. the inner boundary of a planetary nebula
d. the point where synchrotron radiation is created around a pulsar
ANSWER: b
83. What is the approximate size of the Schwarzschild radius of a one solar mass black
hole? a. 3 kilometres
b. 1,500,000 kilometres, the size of the Sun c. 150,000,000 kilometres, or 1 AU
d. 1013 kilometres, or 1 light-year
ANSWER: a
84. How fast is the escape velocity at the event horizon around a black hole? a. It is slower
than the speed of light.
b. It is equal to the speed of light.
c. It is much faster than the speed of light.
d. The escape velocity depends on the mass of the black hole. ANSWER: b
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85. A 3 solar mass black hole has a Schwarzschild radius of about 9 km. How big would the
Schwarzschild radius of a 1000 solar mass black hole be?
a. 90 km
b. 330 km
c. 1000 km d. 3000 km
ANSWER: d
86. Why do astronomers sometimes say “black holes don’t suck”?
a. Black holes can have accretion disks around them.
b. The distance between a black hole event horizon and singularity is not very large. c.
Material that falls into a black hole can come out later.
d. A black hole’s gravity is the same as that of any other object of the same mass.
ANSWER: d
87. What is the term for the distance from a black hole at which the escape velocity is
approximately equal to the speed of light?
a. Lagrangian point
b. Chandrasekhar-Landau limit c. Hubble radius
d. Schwarzschild radius
ANSWER: d
88. What happens when light travels out of a gravitational field, loses energy, and its
wavelength grows longer? a. a gravitational blue shift
b. the solar wind
c. a gravitational red shift
d. a pulsar wind
ANSWER: c
89. Which of the following is an example of time dilation?
a. As material approaches a black hole event horizon, it appears redder and redder.
b. The time that a star spends as a giant is much shorter than its main-sequence lifetime.
c. Pulsars’ pulsation periods slow down as they age.
d. As a star approaches a black hole’s event horizon, it appears to move more and more
slowly.
ANSWER: d
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90. What is the term that describes the slowing of clocks in strongly curved space-time? a.
gravitational radiation
b. time dilation
c. gravitational red shift
d. hyperspace drag
ANSWER: b
91. Which of the following would be most likely to indicate the presence of an isolated black
hole? a. bending of light from background stars
b. emission of light from within an event horizon
c. gravitational effects on a binary companion
d. X-ray emission from an accretion disk
ANSWER: a
92. Which of the following objects is believed to possibly contain a black hole? a. LMC X-3
b. the Orion nebula
c. the central star of the Crab nebula d. PSR 1257+12
ANSWER: a
93. When searching for black holes, what associated phenomena do astronomers search
for? a. single stars that emit large quantities of X-rays
b. X-ray binaries where the compact companion has a mass in excess of 3 solar masses c.
large spherical regions from which no light is detected
d. pulsars with periods of less than one millisecond
ANSWER: b
94. Observations from the Compton Gamma Ray Observatory showed that gamma ray
bursts were located all over the sky. What did astronomers conclude from this?
a. The bursts were produced by stars in the disk of our galaxy.
b. The bursts were associated with planets in our solar system.
c. The bursts were produced by sources in distant galaxies. d. The bursts were produced in
our Sun.
ANSWER: c
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95. What are hypernovae?
a. supernovae that occur when two red dwarfs collide
b. supernovae that occur when 10 solar mass stars explode
c. supernovae that occur when stars more massive than 25 solar masses explode d.
supernovae that occur when two black holes collide
ANSWER: c
96. Which of the following mechanisms would be involved in extracting energy from
compact objects? a. time dilation
b. white holes
c. gravitational redshifts
d. jets and accretion disks
ANSWER: d
97. Cygnus X-1 and LMC X-3 are binary systems with one component not visible. What must
the unseen component masses be for astronomers to be certain that these systems contain
a black hole?
a. less than 0.4 solar masses
b. between 0.4 and 1.4 solar masses
c. less than 5 solar masses d. more than 5 solar masses
ANSWER: d
98. A(n) _____________ _____________ is formed by the expulsion of the outer layers of a
moderate mass star that has a degenerate carbon and oxygen core.
ANSWER: planetarynebula
99. When the pressure of a gas no longer depends on the temperature, the gas is said to be
____________________.
ANSWER: degenerate
100. The maximum mass of a white dwarf is ____________________ solar masses.
ANSWER: 1.4
101. The age of a star cluster can be determined from the ____________________ of the cluster.
ANSWER: turnoffpoint
102. Electrons moving in a strong magnetic field emit ____________________ radiation.
ANSWER: synchrotron
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103. The densest stars in the universe are ____________________ stars. ANSWER: neutron
104. A(n) ____________________ is a rapidly spinning neutron star that accelerates charged
particles near the poles of its magnetic field.
ANSWER: pulsar
105. The ____________________ theory describes pulsars as rotating neutron stars with strong
magnetic fields that confine high speed charged particles in two beams emanating from the
magnetic poles of the neutron star.
ANSWER: lighthouse
106. The ________________ __________ of a black hole in a binary system can emit X-rays, making
it possible for us to detect the presence of the black hole.
ANSWER: accretiondisk
107. The _______________ ______________ of a black hole is the radius from the black hole at which
the escape velocity is equal to the speed of light.
ANSWER: eventhorizon Schwarzschild radius
108. Stars swell into giants when hydrogen is exhausted in their centres. a. True
b. False
ANSWER: True
109. The helium flash is the cause of some supernovae. a. True
b. False
ANSWER: False
110. Helium fusion does not begin until the star has entered the giant region of the H-R
diagram. a. True
b. False
ANSWER: True
111. Even in degenerate matter, pressure depends on temperature. a. True
b. False ANSWER: False
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112. Giant and supergiant stars are rare because that stage of stellar evolution is short. a.
True
b. False
ANSWER: True
113. Young star clusters have bluer turn-off points than old clusters. a. True
b. False
ANSWER: True
114. Planetary nebulae are sites of planet formation. a. True
b. False
ANSWER: False
115. Stars that are less massive than 0.4 solar mass never become giant stars. a. True
b. False
ANSWER: True
116. Once a star ejects a planetary nebula, it becomes a white dwarf. a. True
b. False
ANSWER: True
117. No known white dwarf has a mass greater than the Chandrasekhar-Landau limit. a.
True
b. False
ANSWER: True
118. Because more massive stars have more gravitational energy, they can fuse heavier
nuclear fuels. a. True
b. False
ANSWER: True
119. The Sun will eventually become a supernova. a. True
b. False ANSWER: False
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Name: Class: Date: CHAPTER 8 - THE DEATHS OF STARS
120. Type II supernovae are believed to occur when the cores of massive stars collapse. a.
True
b. False
ANSWER: True
121. Synchrotron radiation occurs when high speed electrons move through a magnetic
field. a. True
b. False
ANSWER: True
122. A Type II supernova produces a planetary nebula. a. True
b. False
ANSWER: False
123. A nova destroys the star and leaves behind a white dwarf. a. True
b. False
ANSWER: False
124. A star begins fusing hydrogen to helium the moment it leaves the main sequence. a.
True
b. False
ANSWER: False
125. The average size of a white dwarf is about the same size as the Earth. a. True
b. False
ANSWER: True
126. Neutron stars have densities roughly the same as that of the atomic nucleus. a. True
b. False
ANSWER: True
127. Neutron stars were first discovered in the 1930s. a. True
b. False ANSWER: False
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128. Pulsars could not be pulsating stars because the pulses are too short. a. True
b. False
ANSWER: True
129. We expect neutron stars to spin rapidly because they conserve angular momentum. a.
True
b. False
ANSWER: True
130. Many pulsars have periods that are gradually getting longer as the spinning neutron
stars lose energy. a. True
b. False
ANSWER: True
131. The event horizon marks the boundary within which the density is roughly the same as
that of the atomic nucleus. a. True
b. False
ANSWER: False
132. Theory predicts that neutron stars may not exceed 3 solar masses. a. True
b. False
ANSWER: True
133. If the accretion disk around a black hole emits X-rays outside the event horizon, the X-
rays can escape the gravitational well.
a. True b. False
ANSWER: True
134. To tell the difference between a neutron star and a black hole in an X-ray binary, we
must find the temperature of the object.
a. True b. False
ANSWER: False
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135. LMC X-3 is a binary system that is believed to contain a black hole. a. True
b. False
ANSWER: True
136. A scientific theory can be proven true if the correct experiments are performed. a. True
b. False
ANSWER: False
137. When a star with a mass comparable to that of the Sun dies, it becomes a black hole. a.
True
b. False
ANSWER: False
138. What properties of degenerate matter are important to the structure of stars? Why?
ANSWER: Answernotprovided.
139. Why does a helium flash occur under some circumstances and not under other
circumstances when helium fusion begins?
ANSWER: Answernotprovided.
140. From what part of the H-R diagram have the giants in a star cluster evolved?
ANSWER: Answernotprovided.
141. Explain how we can find the age of a star cluster.
ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 8 - THE DEATHS OF STARS
142. On the diagram, draw the evolutionary track of the Sun from the time it reaches the
main sequence until it becomes a white dwarf. Label the major stages on this track.
ANSWER: Answernotprovided.
143. Why can't lower main-sequence stars become giant stars?
ANSWER: Answernotprovided.
144. If main-sequence stars are supported by gas pressure, what supports a white dwarf?
ANSWER: Answernotprovided.
145. If white dwarfs have exhausted their fuel, why are they hot?
ANSWER: Answernotprovided.
146. Why can't a lower-mass star generate energy through carbon flash?
ANSWER: Answernotprovided.
147. Why can't a massive star generate energy through iron fusion?
ANSWER: Answernotprovided.
148. What is the difference between a supernova and a nova?
ANSWER: Answernotprovided.
149. What is the difference between a planetary nebula and a supernova remnant?
ANSWER: Answernotprovided.
150. What evidence do we have that some stars lose mass?
ANSWER: Answernotprovided.
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151. If main-sequence stars are supported by gas pressure, what supports a neutron star?
ANSWER: Answernotprovided.
152. Why do we NOT expect to find a 5-solar-mass neutron star? ANSWER:
Answernotprovided.
153. If neutron stars contain no nuclear fuel, why are they hot? ANSWER:
Answernotprovided.
154. Why does our theory predict that neutron stars will spin rapidly? ANSWER:
Answernotprovided.
155. Why does our theory predict that neutron stars will have strong magnetic fields?
ANSWER: Answernotprovided.
156. What evidence do we have that pulsars are neutron stars? ANSWER:
Answernotprovided.
157. What observational evidence do we have that black holes exist? ANSWER:
Answernotprovided.
158. Why might we suspect that a black hole in a binary system could emit X-rays? ANSWER:
Answernotprovided.
159. How can an old pulsar have a very short pulsar period, say less than 0.03 seconds?
ANSWER: Answernotprovided.
160. How are neutron stars and white dwarfs similar? ANSWER: Answernotprovided.
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Name: Class: Date: CHAPTER 9 - THE MILKY WAY GALAXY
1. Who first noticed that for Cepheid variable stars there was a direct relationship between
the luminosity and the period of the variation in their brightness?
a. Annie Cannon
b. Edwin Hubble
c. Harlow Shapley d. Henrietta Leavitt
ANSWER: d
2. Who first calibrated the Cepheid variable stars for use in determining distance? a. Edwin
Hubble
b. Henrietta Leavitt
c. Carl Sagan
d. Harlow Shapley ANSWER: d Cepheid
3. Refer to the figure. A Type II Cepheid with a period of 10 days has been located in a
distant globular cluster. What is the star's absolute magnitude?
a. −6
b. −4
c. −1 d. 0
ANSWER: c
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4. Refer to the figure. A Type II Cepheid with a period of 30 days has been located in a
distant globular cluster. What is the star's absolute magnitude?
a. −6
b. −2
c. −5 d. 0
ANSWER: b
5. Refer to the figure. Polaris is a Type I Cepheid with a period of 4 days. What is its
absolute magnitude? a. +1
b. 0.0 c. -1.0 d. -3.5
ANSWER: d
6. Refer to the figure. If you observe the period of a type II Cepheid and mistakenly think it’s
a type I Cepheid, what incorrect conclusion will you draw?
a. You will measure the wrong period.
b. You will think the Cepheid is farther away than it actually is.
c. You will think the Cepheid is closer than it actually is.
d. You will think the Cepheid is less luminous than it actually is.
ANSWER: b
7. Refer to the figure. A Type I Cepheid with a period of 20 days has been located in a
distant globular cluster. What is its absolute magnitude?
a. -1
b. 0
c. -5 d. -2
ANSWER: c
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8. Refer to the figure. Why is it more difficult to measure the distances to globular clusters
(which contain RR Lyrae stars) than the distances to open clusters (which contain
Cepheids)?
a. RR Lyrae stars are dimmer and harder to see.
b. RR Lyrae stars pulsate so fast that they can’t be measured.
c. RR Lyrae stars are further away than Cepheids.
d. RR Lyrae stars do not have a relationship between period and luminosity.
ANSWER: a
9. What happens with stars when they enter the instability strip? a. They become unstable
and vibrate at variable speeds.
b. They become unstable and pulsate as variable stars.
c. They become unstable and produce bursts of X-rays.
d. They become unstable and turn into fast rotating dwarfs.
ANSWER: b
10. How did Harlow Shapley use the period-luminosity relationship of RR Lyrae variable
stars to determine the size of the Milky Way galaxy?
a. He found the distances to open clusters found throughout the disk of the galaxy.
b. He found the distances to individual variables free-floating in the halo of the galaxy.
c. He determined the proper motion of globular clusters in the outer disk of the galaxy. d. He
found the distances to globular clusters distributed about the centre of the galaxy.
ANSWER: d
11. Before the twentieth century, astronomers lacked knowledge of something, and this
caused them to think that the Sun was at the centre of our star system. What was that
something?
a. globular clusters
b. Cepheid variable stars
c. the dimming effects of gas and dust d. galactic rotation
ANSWER: c
12. How did Harlow Shapley determine where the centre of the galaxy lies? a. He plotted the
distribution of open clusters.
b. He plotted the distribution of globular clusters.
c. He made star counts in every direction of the galactic disk.
d. He measured the amount of dust obscuration in every direction of the galactic disk.
ANSWER: b
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13. Which of the following can be determined using the period-luminosity relation? a. the
radius of the bulge of our galaxy
b. the mass of a star for which the distance is known
c. the temperature of a star for which we know the luminosity
d. the distance to open clusters that contain Cepheid variables
ANSWER: d
14. What part of the Milky Way contains mostly old stars and globular clusters? a. the spiral
arms
b. the spherical halo component
c. the smooth disk component
d. the nucleus
ANSWER: b
15. What is the main component of the central bulge of our galaxy? a. gas and dust
b. population I stars
c. stars associated with the spherical component of our galaxy d. stars associated with the
disk component of our galaxy
ANSWER: c
16. If a star with a high speed with respect a typical disk star is found, what other property
would you expect it to have?
a. young age
b. high luminosity
c. low metal content compared to the Sun d. high mass
ANSWER: c
17. Which of the following is a characteristic of the stars of the disk component of our
galaxy? a. young stars
b. randomly inclined orbits c. old stars
d. low metal abundance
ANSWER: a
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18. What behaviour of galactic rotation curves suggests the existence of dark matter in an
extended halo? a. Small velocities are seen at large distances from the galactic centre.
b. Small velocities are seen at distances close to the galactic centre.
c. Large velocities are seen at large distances from the galactic centre.
d. Large velocities are seen at distances close to the galactic centre.
ANSWER: c
19. Our galaxy is suspected to be surrounded by a dark halo. What is it about the disk of the
galaxy that makes us suspect this?
a. It rotates faster than expected in its outer region.
b. It rotates more slowly than expected in its outer region.
c. It is only visible during a total eclipse of our Sun.
d. It is surrounded above, below, and well beyond by the brightly glowing corona.
ANSWER: a
20. Which of the following is believed to make up most of the extended galactic halo? a. dark
matter
b. faint brown dwarfs c. G, K, and M stars d. globular clusters
ANSWER: a
21. Why are O and B stars good tracers of spiral structure?
a. They are young and luminous.
b. They are old and have been part of the galaxy for a long time. c. They are young and
moving with large radial velocities.
d. They were formed in the galaxy’s halo.
ANSWER: a
22. If other galaxies are like the Milky Way, which parts of them should contain luminous O
and B type stars? a. the halos
b. the bulges
c. the spiral arms
d. the globular clusters
ANSWER: c
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23. Why are stars like the Sun a poor tracer of the Milky Way’s spiral structure? a. The spiral
arms do not contain any solar-type stars.
b. Stars like the Sun are extremely rare.
c. Stars like the Sun were formed before the galaxy’s disk.
d. Stars like the Sun have moved away from their original birthplaces.
ANSWER: d
24. What do radio maps of the spiral arms of our galaxy show?
a. They reveal that our galaxy is a grand design spiral.
b. They map the location of dense neutral hydrogen clouds.
c. They reveal that the Sun is currently located in the centre of a spiral arm.
d. They map the location of hot O and B stars by the radio radiation they emit.
ANSWER: b
25. Which of the following are associated with the spiral arms of a galaxy? a. young, massive
stars
b. nuclear bulges
c. metal-poor stars
d. million-solar-mass black holes
ANSWER: a
26. Why do radio maps of our galaxy show spiral arms? a. The arms have larger Doppler
shifts.
b. The gas in the spiral arms is very hot.
c. The dust in spiral arms is denser.
d. The gas in spiral arms is denser.
ANSWER: d
27. If spiral density waves were the only thing producing spiral arms, what result would be
expected? a. All spiral arms would be gas-free and dust-free.
b. All galaxies would have only two smooth spiral arms.
c. The Milky Way would show an irregular pattern of short arms.
d. The halo component of the Milky Way would show spiral arms as well. ANSWER: b
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28. Which component of the Milky Way is associated with higher metal abundance? a. dark
halo
b. disk component c. halo
d. globular clusters
ANSWER: b
29. Where are Population II stars found? a. in the galaxy’s globular clusters
b. in the disk of the galaxy
c. in the centre of the galaxy
d. in the galaxy’s spiral arms
ANSWER: a
30. The age of the Milky Way galaxy has been estimated to be at least 13 billion years. What
is this estimate based on? a. observations of open clusters
b. observations of globular clusters
c. 21-cm radiation from H I regions
d. radiation produced at the centre of the galaxy
ANSWER: b
31. You observe a metal-rich star in a nearly circular orbit. Which of the following is most
likely to apply to the star? a. The star is a halo population star.
b. The star is an extreme Population II star.
c. The star is a disk population star.
d. The star is an intermediate Population II star.
ANSWER: c
32. What are the orbits of population I stars like?
a. circular, confined to the disk of the galaxy
b. very elliptical, confined to the disk of the galaxy
c. very elliptical, randomly inclined to the disk of the galaxy d. circular, randomly inclined to
the disk of the galaxy
ANSWER: a
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33. Why do younger stars have more heavy elements?
a. because old stars destroy heavy elements as they age
b. because the heavy elements were made in previous generations of stars
c. because young stars burn their nuclear fuels faster
d. because heavy elements haven't had time to settle to the core of these younger stars
ANSWER: b
34. What does the chemical abundance found in population I stars tell us about them? a. It
indicates that they are all massive stars.
b. It indicates that they were formed before the population II stars.
c. It indicates that they contain very few heavy metals compared to halo stars.
d. It indicates that the material they formed from had been enriched with material from
supernovae.
ANSWER: d
35. Which of the following are the oldest members of the Milky Way? a. globular clusters.
b. population I stars.
c. disk population stars.
d. G and F stars.
ANSWER: a
36. What kind of orbits did the first stars to form in our galaxy have? a. circular orbits
b. hyperbolic orbits
c. slightly elliptical orbits, all in the same plane
d. highly elongated elliptical orbits
ANSWER: d
37. According to the traditional theory, how did the galaxy form?
a. from a large cloud of material that broke off a larger galaxy
b. from the collapse of a large spherical cloud of gas that was rotating very slowly c. from
material that had been ejected in the violent explosion of a dying galaxy
d. as a result of mergers between several smaller groups of gas, dust, and stars
ANSWER: b
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38. How does the traditional theory of the formation of the galaxy explain the origin of
globular clusters? a. They formed in the disk and were later ejected to the halo.
b. They built up over time from the collisions of stars in the halo.
c. They formed in other galaxies and were captured by close interactions.
d. They formed early on during the free-fall collapse of the proto-galactic material.
ANSWER: d
39. Which constellation lies in the direction of the centre of our galaxy? a. Orion
b. Sagittarius c. Ursa Major d. Monoceros
ANSWER: b
40. Elements heavier than iron are very scarce. Where are these elements mostly made? a.
in galactic halos and stars
b. in the interstellar medium and galactic halos
c. in supernovae and stars
d. in white dwarfs and pulsars
ANSWER: c
41. What is the best evidence that Sagittarius A* is a black hole at the centre of the Milky
Way galaxy?
1. Orbits of stars indicate a mass several million times that of the Sun within a very
small volume.
2. Sagittarius A* is a powerful radio source.
3. No visible light from Sagittarius A* reaches the Earth.
4. Radio maps of the region around Sagittarius A* show complicated gas structures
believed to be related to massive star formation.
ANSWER: a
42. What type of radiation do we detect from the energy source at the centre of our galaxy?
a. ultraviolet light
b. visible light
c. X-rays
d. gamma rays ANSWER: c
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43. Henrietta Leavitt discovered the period-luminosity relationship for _______________
_______________. ANSWER: Cepheidvariables
44. In the diagram, the approximate absolute magnitude of a Type II Cepheid with a period
of 30 days is _________________.
ANSWER: −2
45. ______________ ______________ are groups of 100,000 to 1,000,000 population II stars firmly
bound together by gravity.
ANSWER: Globularclusters
46. Globular clusters are primarily found in the _________________ component of the galaxy.
ANSWER: halo
47. The rotation curve of the galaxy provides evidence for the existence of the _____________
_______________ that extends beyond the halo of the galaxy.
ANSWER: extendedhaloORdarkhalo
48. The __________________ of the galaxy contains population I stars, open clusters, and gas
clouds.
ANSWER: disk
49. The centre of our galaxy is believed to be occupied by the radio source known as
____________________.
ANSWER: SgrA*ORSagittariusA*
50. The centre of our galaxy is located in the direction of the constellation of Orion. a. True
b. False ANSWER: False
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51. Harlow Shapley found the distance to the centre of the galaxy by studying the distance
to open clusters. a. True
b. False
ANSWER: False
52. The disk of the Milky Way is approximately 20,000 light years in diameter. a. True
b. False
ANSWER: False
53. The rapid rotation of the outer disk suggests that our galaxy is more massive than
previously thought. a. True
b. False
ANSWER: True
54. Old stars are poor in heavy atoms because there were very few previous generations of
stars before the old stars formed.
a. True b. False
ANSWER: True
55. The disk of the galaxy is older than the halo. a. True
b. False
ANSWER: False
56. Spiral tracers tend to be old, luminous stars. a. True
b. False
ANSWER: False
57. Giant molecular cloud complexes are located in spiral arms. a. True
b. False ANSWER: True
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58. The density wave theory explains spurs and branches along the spiral arms. a. True
b. False
ANSWER: False
59. The centre of our galaxy shows signs of past eruptions. a. True
b. False
ANSWER: True
60. The period-luminosity relationship is primarily used for main sequence stars. a. True
b. False
ANSWER: False
61. The orbits of halo stars are typically circular and have a low inclination with respect to
the disk. a. True
b. False
ANSWER: False
62. Population I stars contain more metals than Population II stars. a. True
b. False
ANSWER: True
63. Population II stars contain more metals than Population I stars. a. True
b. False
ANSWER: False
64. Why are Cepheid variable stars important in our study of the Milky Way galaxy?
ANSWER: Answernotprovided.
65. What is the difference between an open cluster, an association, and a globular cluster?
In which parts of the galaxy is each found?
ANSWER: Answernotprovided.
66. Why does the rotation of our galaxy suggest that it is more massive than previously
thought?
ANSWER: Answernotprovided.
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67. What is the difference between a population I star and a population II star? ANSWER:
Answernotprovided.
68. Why does the average chemical composition of stars now forming differ from that of
older stars? ANSWER: Answernotprovided.
69. How do theories of the origin of the Milky Way explain its halo? ANSWER:
Answernotprovided.
70. Why are all spiral tracers young? ANSWER: Answernotprovided.
71. How does the density wave theory explain the presence of young stars in the spiral
arms? ANSWER: Answernotprovided.
72. What evidence do we have that the centre of our galaxy is a powerful source of energy?
A massive black hole? ANSWER: Answernotprovided.
73. Describe the central few light-years of our galaxy. ANSWER: Answernotprovided.
74. Discuss how Harlow Shapley determined the structure of the Milky Way galaxy from his
study of globular clusters. ANSWER: Answernotprovided.
75. Discuss how astronomers know that our galaxy contains spiral arms in its disk.
ANSWER: Answernotprovided.
76. Compare and contrast the properties of disk and halo stars. ANSWER:
Answernotprovided.
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- GALAXIES
1. Based on statistical studies, what is the most common type of galaxy in the universe
expected to be? a. barred spiral galaxies
b. dwarf elliptical galaxies
c. irregular galaxies
d. giant elliptical galaxies
ANSWER: b
2. Which of the following is an irregular galaxy that is passing close to the Milky Way and is
expected to merge with the Milky Way in the future?
a. the Andromeda galaxy
b. the Small Magellanic Cloud
c. M87
d. the Whirlpool galaxy
ANSWER: b
3. What type of galaxies do astronomers believe are the most common? a. elliptical
b. spiral
c. irregular
d. barred spiral
ANSWER: a
4. Which of the following is the best example of a selection effect?
a. Globular clusters are not included in catalogues of galaxies.
b. The nearest quasars are not included in quasar catalogues.
c. Bright spiral galaxies are not included in catalogues of nearby galaxies.
d. Dwarf elliptical galaxies are not included in catalogues of nearby galaxies.
ANSWER: d
5. If the Hubble Space Telescope were used to take pictures of the entire sky, roughly how
many galaxies would those pictures contain?
a. 1million
b. 10 million
c. 1 billion
d. 100 billion
ANSWER: d
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6. What factor below is the most important when trying to classify a galaxy as spiral or
elliptical? a. the amount of dust and gas in the galaxy
b. the galaxy’s location
c. the number of satellite galaxies
d. the mass of the galaxy
ANSWER: a
7. What is the primary factor used in determining the classification for an elliptical galaxy?
a. size
b. shape c. mass d. colour
ANSWER: b
8. What does an elliptical galaxy contain?
a. mostly lower main-sequence stars and giants
b. mostly upper main-sequence stars
c. mostly upper main-sequence stars and gas and dust
d. roughly equal numbers of upper and lower main-sequence stars
ANSWER: a
9. What does a spiral (S or SB) galaxy contain?
a. mostly lower main-sequence stars and giants
b. upper and lower main-sequence stars, gas and dust c. mostly upper main-sequence stars,
gas and dust
d. mostly upper main-sequence stars
ANSWER: b
10. What does an irregular galaxy contain?
a. mostly lower main-sequence stars and giants
b. mostly upper main-sequence stars and giants
c. mostly upper main-sequence stars and gas and dust
d. upper and lower main-sequence stars and gas and dust
ANSWER: d
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11. What kind of galaxies contain large clouds of gas and dust, and both young and old stars,
but have no obvious spiral arms or nucleus?
a. irregular
b. lenticular
c. elliptical
d. barred spiral
ANSWER: a
12. What type of galaxy has an elongated nucleus with a spiral structure extending from the
ends of the elongations? a. spiral
b. barred spiral c. elliptical
d. irregular
ANSWER: b
13. Which of the following statements about galaxies is correct?
a. Most galaxies in the universe are about the same size as the Milky Way.
b. Galaxies come in a wide variety of sizes and shapes, but are all very blue in colour. c.
Small galaxies outnumber large galaxies.
d. Galaxies come in a wide variety of sizes and shapes, but are all very red in colour.
ANSWER: c
14. How is a lenticular galaxy different from a normal spiral galaxy? a. It is more flattened.
b. It has more spiral arms.
c. It is more spherical in shape.
d. It is more chaotic and irregular.
ANSWER: a
15. What kind of galaxy is the Milky Way? a. spiral
b. barred spiral c. elliptical
d. lenticular
ANSWER: b
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- GALAXIES
16. Which of the following types of galaxies are frequently found in large clusters? a. spiral
b. lenticular
c. elliptical
d. barred spiral
ANSWER: c
17. Which of the following sequences sorts the galaxy types according to the rate at which
new stars are forming, from highest rate to lowest rate?
a. elliptical, spiral, irregular
b. spiral, elliptical, irregular
c. elliptical, irregular, spiral d. spiral, irregular, elliptical
ANSWER: d
18. What do tidal tails, multiple nuclei, and shells of stars have in common? a. All are found
in clusters of galaxies.
b. All are found near active galactic nuclei.
c. All are characteristics of spiral galaxies.
d. All are related to galaxy interactions.
ANSWER: d
19. What is a mega-parsec equivalent to? a. 3.26 light years
b. 206,265 AU
c. 1000 parsecs
d. 3.26 million light years
ANSWER: d
20. What is the Hubble constant essentially a measure of? a. the number of galaxies in the
universe
b. the expansion rate of the universe
c. the age of the Milky Way galaxy
d. the amount of dark matter in an average galaxy ANSWER: b
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Name: Class: Date: CHAPTER 10
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21. Edwin Hubble measured the distance to the Andromeda Galaxy. How did he do that? a.
He applied the period-luminosity relation to Cepheids.
b. He measured the parallax of the Andromeda Galaxy.
c. He estimated the number of galaxies in the universe.
d. He applied the white dwarf brightness relation.
ANSWER: a
22. What property of a galaxy do you need to measure before you can determine its size or
luminosity? a. colour
b. mass
c. shape d. distance
ANSWER: d
23. You observe a Cepheid variable star in a nearby galaxy. How would you determine its
distance? a. apply the peak colour-magnitude relation
b. apply the period-luminosity relation
c. apply the Hubble Law
d. measure the parallax
ANSWER: b
24. What distance method is used to calibrate galaxy distances? a. parallax
b. radar measurements
c. variable stars
d. the moving cluster method
ANSWER: c
25. If you wanted to measure the distance to a galaxy, what kind of objects within it could
you observe? a. Cepheid variable stars
b. Herbig-Haro objects
c. large globular clusters
d. dust lanes ANSWER: a
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26. The Hubble Law describes a relationship between two characteristics of a galaxy. What
are they? a. mass and luminosity
b. distance and luminosity
c. mass and recession velocity
d. distance and recession velocity
ANSWER: d
27. What distance method is used to determine the distance to the most distant galaxies? a.
radar echo
b. supernova observations
c. the period-luminosity relationship of variable stars d. parallax
ANSWER: b
28. How would you use the Hubble Law to measure the distance to a galaxy?
a. Measure its apparent recession velocity and divide by the age of the universe. b. Measure
its Cepheid variables and multiply by the Hubble constant.
c. Measure its apparent recession velocity and divide by the Hubble constant. d. Measure its
apparent recession velocity and add it to the Hubble constant.
ANSWER: c
29. If Galaxy A is found to have a recessional velocity four times greater than that of Galaxy
B, what can you say about their relative distances from Earth?
a. Galaxy A is one quarter as far away as Galaxy B.
b. Galaxy A is half as far away as Galaxy B.
c. Galaxy A is twice as far away as Galaxy B.
d. Galaxy A is four times as far away as Galaxy B.
ANSWER: d
30. If H (the Hubble constant) equals 70 km/sec/Mpc, then approximately how far away is a
galaxy with a radial velocity of 2100 km/sec?
a. 30 Mpc
b. 2030 Mpc
c. 2170 Mpc
d. 147,000 Mpc
ANSWER: a
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31. If H (the Hubble constant) equals 70 km/sec/Mpc, then approximately how far away is a
galaxy with a radial velocity of 7000 km/sec?
a. 10 Mpc
b. 70 Mpc
c. 100 Mpc d. 700 Mpc
ANSWER: c
32. If a galaxy has a radial velocity of 8000 km/sec and the Hubble constant is 70
km/sec/Mpc, what is the distance to this galaxy?
a. 8.75×10-3 Mpc b. 114 Mpc
c. 8.75×103 Mpc d. 2.4×109 Mpc
ANSWER: b
33. If a disk galaxy is reasonably close and edge-on, the Doppler shift of the galaxy disk
material relative to the centre can be measured at several distances from the galaxy's
centre. What does this measurement tell us about the galaxy?
a. the galaxy’s luminosity
b. the galaxy’s diameter
c. the galaxy’s mass
d. the galaxy’s velocity dispersion curve
ANSWER: c
34. How might the mass of a single galaxy be found? a. by the double galaxy method
b. by the rotation curve method
c. by the cluster method
d. by the main-sequence fitting method ANSWER: b
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35. Where is most of the mass of a galaxy found? a. in the massive O and B stars
b. in the H II regions
c. in the dark matter
d. in the disk
ANSWER: c
36. What can the rotation curve of a galaxy be used to determine? a. the mass of the galaxy
b. the radius of the galaxy
c. the luminosity of the galaxy
d. the relative amount of gas and dust in the galaxy
ANSWER: a
37. Observations of galaxies and clusters of galaxies indicate that a percentage of the matter
in the universe is dark matter. What is that percentage?
a. 5 %
b. 25 %
c. 35 % d. 95 %
ANSWER: d
38. Why are supermassive black holes believed to be located at the centre of many galaxies?
a. because the rotation curve of the galaxy indicates that 90% of the galaxy is dark matter
b. because the orbital motion of material near the centre is very fast and indicates a very
massive core
c. because the shape of the bulge in all spiral galaxies can only be supported by a
supermassive black hole d. because the spiral structure requires a black hole to maintain
the spiral arms
ANSWER: b
39. Which of the following best describes poor clusters?
a. They contain lots of young stars and are found in the disk of a spiral galaxy. b. They
contain more than 1000 galaxies and are generally elliptical in shape. c. They contain fewer
than 1000 galaxies and have irregular shapes.
d. They are found in the nucleus of the galaxy.
ANSWER: c
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40. Which of the following generally contain well over 1000 galaxies (mainly ellipticals)
packed closely together? a. local groups
b. poor clusters c. rich clusters d. tidal tails
ANSWER: c
41. Which of the following types of objects is the Milky Way part of? a. a rich cluster
b. a poor cluster
c. the Virgo cluster d. a globular cluster
ANSWER: b
42. What is the Coma cluster?
a. It is the galactic cluster that contains the Milky Way.
b. It is the oldest known cluster of galaxies.
c. It is a cluster that contains mostly spiral galaxies and very few elliptical galaxies. d. It is a
rich cluster of galaxies near the Local Group.
ANSWER: d
43. Which of the following is the Milky Way galaxy a part of? a. the Virgo cluster
b. the Large Magellanic Cloud
c. the Small Magellanic Cloud
d. the Local Group
ANSWER: d
44. When does gravitational lensing occur?
a. when light passes near a massive object and is deflected by the object's gravitational field
b. when a galaxy has a central black hole with an accretion disk
c. when the mass of a galaxy is greater than expected from the luminosity of the galaxy
d. when the mass of a galaxy is less than expected from the luminosity of the galaxy
ANSWER: a
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45. What evidence leads astronomers to conclude that galaxies’ shapes may be affected by
the environment in which they are located?
a. the different rates of star formation in spiral and elliptical galaxies
b. the different amounts of gas found in spiral and elliptical galaxies
c. the large range of sizes of elliptical galaxies found in clusters
d. the different fractions of galaxy types in rich clusters and poor clusters
ANSWER: d
46. Which of the following has the largest diameter? a. the Milky Way galaxy
b. the Large Magellanic Cloud
c. the Local Group
d. the Andromeda galaxy
ANSWER: c
47. Where was gravitational lensing first observed? a. near the Sun during an eclipse
b. in galaxy clusters
c. in a prism held by Newton
d. in quasars
ANSWER: a
48. How did the discovery of gravitational lensing affect our knowledge of quasars?
a. It showed that some quasars are located within the Local Group of galaxies.
b. It showed that quasars are located in the halo of the Milky Way.
c. It showed that quasars are much farther away than the distant galaxies that form the
gravitational lenses. d. It proved the existence of super-massive black holes at the centres of
active galactic nuclei.
ANSWER: c
49. What information about a cluster of galaxies can lensing of background galaxies by the
cluster be used to determine?
a. luminosity b. mass
c. distance d. diameter
ANSWER: b
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50. Why do we expect galaxies to collide fairly often?
a. Galaxy separation distances are not that large compared to their sizes. b. Galaxies contain
large amounts of neutral hydrogen.
c. Galaxies’ large masses cause gravitational attraction.
d. Galaxies are moving quickly toward each other.
ANSWER: a
51. Which of the following describes part of the evolution of an elliptical galaxy?
a. It will turn into an irregular galaxy when it has used up all of its gas and dust.
b. It may result from the collision and merger of spiral galaxies.
c. It evolves from a single spiral galaxy when the spiral has used up all of its gas and dust.
d. It would become a starburst galaxy if it were to move through the hot intergalactic
medium of a cluster.
ANSWER: b
52. Which of the following are produced when two galaxies pass near each other and pull
large streamers of stars, gas, and dust away from each other?
a. ring galaxies
b. rotation curves
c. tidal tails
d. irregular galaxies
ANSWER: c
53. Which of the following best describes starburst galaxies?
a. They contain a large number of very young stars, but very little evidence of gas clouds. b.
They contain a large number of very old stars and almost no gas or dust.
c. They are often associated with galaxy collisions.
d. They are commonly found in rich clusters.
ANSWER: c
54. Which of the following describes the way that ring galaxies are believed to form?
a. when two spiral galaxies collide, along a direction parallel to one galaxy’s disk
b. when two galaxies of different sizes collide along a direction perpendicular to the larger
galaxy’s disk c. when two elliptical galaxies collide at a position offset from their centres
d. when more than two galaxies collide at the same time, along a straight line
ANSWER: b
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55. What does the term “galactic cannibalism” refer to?
a. binary galaxies
b. the merging of galaxies
c. galaxies drawing in gas from the intergalactic medium
d. the destruction of a galaxy’s globular clusters by the galaxy’s nucleus
ANSWER: b
56. What is the defining feature of Seyfert galaxies?
a. They are more common in isolated galaxies than in close pairs of galaxies.
b. They have spectra which show that gas in their cores is hot and moving quickly. c. They
generally show redshifts greater than 6.
d. They are a type of elliptical galaxy.
ANSWER: b
57. What is the major observational difference between a Seyfert galaxy and a normal spiral
galaxy? a. Normal spiral galaxies usually have shorter spiral arms.
b. Normal spiral galaxies never contain a supermassive black hole at their centre.
c. The central region of a Seyfert galaxy is much brighter.
d. Seyfert galaxies don't contain any star formation.
ANSWER: c
58. What is look-back time?
a. the time it takes for the light from an object to reach Earth
b. the time it takes for a distant object to form
c. the time it takes for an object to orbit once around the Milky Way d. the age of an object in
light-years
ANSWER: a
59. Which of the following are spiral galaxies that have small luminous nuclei? a. active
b. radio c. Seyfert d. blazar
ANSWER: c
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60. What inflates the lobes of a radio galaxy?
a. jets of excited gas flowing from the central galaxy
b. jets of high energy sound waves flowing from the central galaxy
c. a disk of ionized material that orbits very near a supermassive black hole d. dark clouds
of very cold gas and dust
ANSWER: a
61. What is located between the lobes of a double-lobed radio source? a. a pulsar
b. a galaxy
c. a galaxy cluster
d. regions with hot gas but no stars
ANSWER: b
62. Suppose you want to know the distance to a particular galaxy. What’s the biggest
problem with using type 1a supernovae to measure the distance?
a. Supernovae are extremely luminous and can outshine their galaxies.
b. Supernovae all have about the same luminosity.
c. Because supernovae are very energetic, they are not well understood. d. Supernovae are
rare, so you might have to wait a long time.
ANSWER: d
63. Centaurus A is a radio galaxy that has a visible galaxy at its centre. This central elliptical
galaxy of Centaurus A is encircled by a ring of gas and dust, unlike most elliptical galaxies.
The dust ring orbits about an axis that is perpendicular to the axis of rotation of the central
elliptical galaxy. What does this suggest about this central elliptical galaxy of Centaurus A?
a. The radio jets have caused the dust disk to be driven around the elliptical galaxy.
b. There are at least two black holes at the centre of the elliptical galaxy.
c. Centaurus A is probably the result of a merger of an elliptical galaxy and a spiral galaxy. d.
Dust is produced as the jets interact with the intergalactic medium.
ANSWER: c
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64. Why were quasars so mysterious when first discovered?
a. Quasars emitted radio energy like radio galaxies, but looked like stars in visible light.
b. Quasars showed significant gravitational lens effects.
c. The spectra of quasars looked like those of M dwarfs.
d. The large redshifts originally indicated that they were orbiting the centre of the Milky
Way.
ANSWER: a
65. Which of the following emits large amounts of energy, but photographically appears to
be a single point of light, much like a star?
a. an elliptical galaxy
b. a spiral galaxy
c. a quasar
d. a double-lobed radio source
ANSWER: c
66. If the redshifts of quasars arise from the expansion of the universe, yet they have
brighter magnitudes than galaxies with the same redshifts, what must be generally true of
quasars?
a. They are very small.
b. They are within the Local Group.
c. They are moving toward Earth with a large radial velocity. d. They emit a very large
amount of energy per second.
ANSWER: d
67. Which of the following indicates that quasars must be small? a. They have high radial
velocities.
b. They are surrounded by quasar fuzz.
c. They radiate huge amounts of energy.
d. They fluctuate rapidly on time scales as short as a few hours.
ANSWER: d
68. Why do we suspect that quasars are the active centres of galaxies?
a. “Fuzz” around the central luminous regions looks like a collection of normal stars. b. A
few quasars have large redshifts.
c. The central regions of some quasars fluctuate rapidly.
d. Quasars emit large amounts of X-rays.
ANSWER: a
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69. Which type of active galaxy can be seen at the greatest distance? a. Seyfert galaxies
b. radio galaxies
c. quasars
d. BL Lac objects
ANSWER: c
70. The hydrogen Balmer line Hβ has a wavelength of 486.1 nanometres in the laboratory.
The same line is observed in a quasar at 2430.5 nm. What is the change in wavelength (in
nm) for the line in this quasar spectrum?
a. 0
b. 486.1
c. 1944.4 d. 2430.5
ANSWER: c
71. How does the unified model describe an active galactic nucleus?
a. as a supermassive black hole at the centre of a normal spiral galaxy
b. as a supermassive black hole surrounded by an accretion disk and a dense disk of gas c.
as an accretion disk around a neutron star
d. as a gravitationally lensed high-redshift galaxy
ANSWER: b
72. What produces the energy from an active galactic nucleus? a. the collision of two spiral
galaxies
b. matter flowing out of a central star-forming region
c. the collision of two radio jets
d. matter flowing into a supermassive black hole
ANSWER: d
73. In the unified model of active galactic nuclei, what is the broad line region in an active
galactic nucleus?
a. It is composed of clouds of gas and stars moving at very high orbital velocities near a
supermassive black
hole.
b. It is composed of a super massive black hole surrounded by empty space.
c. It is the region responsible for producing the bright continuous radiation from within the
event horizon. d. It is the region responsible for the narrow absorption lines seen in Type 2
Seyfert galaxies.
ANSWER: a
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74. According to the unified model of active galactic nuclei, what is observed if our line of
sight is parallel to the plane of the dense disk of an active galactic nucleus?
a. no spectral emission lines
b. broad spectral lines
c. narrow spectral lines d. a thin accretion disk
ANSWER: c
75. What kind of radiation is produced by the radio lobes that are on each side of some
radio galaxies, and also by the jets from them?
a. mainly 21-cm radiation
b. mainly synchrotron radiation
c. mainly black body radiation
d. mainly emission lines due to hydrogen
ANSWER: b
76. What is the most important difference between an active galactic nucleus and a
dormant black hole at the centre of a galaxy?
1. Active galactic nuclei are only found in elliptical galaxies, but dormant black holes
are found in all galaxy types.
2. The black holes in active galactic nuclei have much larger masses than those of
dormant black holes.
3. The black holes in active galactic nuclei have much smaller masses than those of
dormant black holes.
4. The black holes in active galactic nuclei have much more matter flowing into them.
ANSWER: d
77. What is indicated by the fact that the lobes in a double-lobed radio source radiate
synchrotron radiation? a. High speed electrons are spiralling through a magnetic field.
b. The source of the radio jets must be a black hole.
c. The source of the radio energy is rotating rapidly.
d. The central galaxy must be a giant elliptical galaxy. ANSWER: a
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78. What process is most likely to turn a dormant black hole at the centre of a galaxy into an
active galactic nucleus? a. a galaxy collision
b. a quasar phase
c. a burst of star formation
d. a nearby supernova
ANSWER: a
79. How do astronomers know that there is activity in the nuclei of some galaxies?
a. Their nuclei are much brighter than expected.
b. The orbits of stars near the centre of the galactic nuclei are faster than expected. c. The
luminosity of the nuclei varies over time.
d. The colour of the nuclei is different than expected.
ANSWER: c
80. Why do astronomers believe that supermassive black holes are the source of energy for
active galactic nuclei? a. Such black holes have been found at the centre of most galaxies,
both active and inactive.
b. Radio jets are seen from low mass black holes plus accretion disks inside our galaxy.
c. Jets and accretion disks have been observed in active galaxies.
d. Only black holes can produce so much energy in such a small region.
ANSWER: d
81. How does the unified model of active galactic nuclei (AGN) explain blazars?
a. Blazars are Seyfert galaxies seen edge-on.
b. Blazars are regions of the intergalactic medium where gas has been heated by a nearby
AGN. c. Blazars are relativistic jets from an AGN pointed toward our light of sight.
d. Blazars are newly formed AGNs from a recent galactic collision.
ANSWER: c
82. What is the most common redshift of quasars? a. less than 0.1
b. 0.1 to 0.5
c. about 2
d. greater than 6
ANSWER: c
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83. How does the study of quasars reveal information about the history of the universe? a.
Quasars contain stars of all ages.
b. Quasars are very distant, so we see them as they were in the past.
c. Quasars typically act as host galaxies for gravitational lensing.
d. Quasars generate their energy in very small volumes of space.
ANSWER: b
84. Mathematical models indicate that one type of galaxy is produced by high-speed
collisions in which a smaller galaxy passes through a larger galaxy almost perpendicular to
the disk of the larger galaxy. What is this type of galaxy called?
a. ring
b. spiral
c. antenna d. irregular
ANSWER: a
85. ____________________ galaxies have a definite disk component, but contain no evidence of
spiral pattern, few hot young stars, and little gas and dust.
ANSWER: S0
86. The units of the Hubble constant are ____________________.
ANSWER: km/sec/Mpc
87. Measuring the Doppler shift of material at various distances from the centre of a galaxy
can be used to construct a(n) ________________ _____________ for that galaxy.
ANSWER: rotationcurve
88. Due to the extremely rapid orbital velocities of material near the centres of many
galaxies, these galaxies are believed to contain ___ ________________ ___________ _________ at their
centres.
ANSWER: asupermassiveblackhole
89. ____________________ clusters of galaxies contain closely spaced galaxies, and often contain
giant elliptical galaxies and a hot intergalactic medium.
ANSWER: Rich
90. The spectrum of a(n) ____________________ consists of a continuum and a few highly
redshifted emission lines due to hydrogen.
ANSWER: quasar
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91. The high ____________________ of quasars reveals to astronomers that they must be very
distant. ANSWER: redshift
92. The ________________ ____________ describes blazars, Seyferts, and radio lobe galaxies as
being produced by a dense disk of gas and a hot accretion disk around a supermassive
black hole at the core of a galaxy.
ANSWER: unifiedmodel
93. A(n) ___________________ is observed if our line of sight is along the rotation axis of an
active galactic nucleus.
ANSWER: blazar
94. Elliptical galaxies contain more gas, dust, and young stars than Sa galaxies. a. True
b. False
ANSWER: False
95. Cepheid variable stars are more luminous than the Sun. a. True
b. False
ANSWER: True
96. The look-back time is numerically equal to the distance to a galaxy in light-years. a. True
b. False
ANSWER: True
97. The rotation curve method can only be applied to pairs of galaxies orbiting each other. a.
True
b. False
ANSWER: False
98. Some large clusters of galaxies do not appear to contain enough mass to hold
themselves together. a. True
b. False ANSWER: True
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99. If H equals 50 km/sec/Mpc, then a galaxy with a radial velocity of 50,000 km/sec will
have a distance of about 1 Mpc.
a. True b. False
ANSWER: False
100. When two galaxies collide, they pass through each other and their stars almost never
collide. a. True
b. False
ANSWER: True
101. When a large galaxy collides with a small galaxy, the smaller galaxy may be pulled
apart by tidal forces. a. True
b. False
ANSWER: True
102. Poor clusters of galaxies often contain an excess of E and S0 galaxies. a. True
b. False
ANSWER: False
103. The Large and Small Magellanic clouds are satellite galaxies of the Milky Way. a. True
b. False
ANSWER: True
104. Elliptical galaxies are primarily made up of massive O and B stars. a. True
b. False
ANSWER: False
105. The Local Group of galaxies is dominated by the presence of spiral galaxies. a. True
b. False ANSWER: False
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106. The Milky Way galaxy is not a radio galaxy; it emits no radio radiation. a. True
b. False
ANSWER: False
107. Double-lobed radio galaxies appear to be emitting jets of gas and radiation. a. True
b. False
ANSWER: True
108. The radio radiation emitted by a radio lobe is mainly synchrotron radiation. a. True
b. False
ANSWER: True
109. Seyfert galaxies are spiral galaxies with active cores. a. True
b. False
ANSWER: True
110. Radio lobes are held together by their magnetic fields. a. True
b. False
ANSWER: False
111. The rapid fluctuations of quasars show that the energy-emitting portions of these
objects must be very small. a. True
b. False
ANSWER: True
112. Quasar redshifts are usually larger than the redshifts of the visible galaxies. a. True
b. False
ANSWER: True
113. If a quasar has a redshift of 0.98, then it is receding from Earth at 98 percent of the
speed of light. a. True
b. False ANSWER: False
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114. Object of known brightness that astronomers use to find distance is called the Hubble
constant. a. True
b. False
ANSWER: False
115. Object of known brightness that astronomers use to find distance is called a standard
candle. a. True
b. False
ANSWER: True
116. The rotation curve method is the most precise method for measuring the mass of a
disk galaxy. a. True
b. False
ANSWER: True
117. Some quasars have fuzz around them that produces spectra similar to those of normal
galaxies. a. True
b. False
ANSWER: True
118. Explain why good distance indicators must be luminous objects. Why must they be
unambiguously recognizable?
ANSWER: Answernotprovided.
119. How does the use of H II regions to find a galaxy's distance differ from the use of
Cepheid variables?
ANSWER: Answernotprovided.
120. How does the rotation curve method differ from the analysis of binary stars?
ANSWER: Answernotprovided.
121. What assumptions do we make when we use the Hubble constant to estimate the
distance to a galaxy?
ANSWER: Answernotprovided.
122. Why can’t galaxy evolution go from elliptical to spiral to irregular?
ANSWER: Answernotprovided.
123. What evidence do we have that large galaxies cannibalize small galaxies?
ANSWER: Answernotprovided.
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124. Propose a hypothesis to explain why rich galaxy clusters have a larger proportion of
elliptical and S0 galaxies than other galaxy clusters.
ANSWER: Answernotprovided.
125. Why is the number of galaxies in the Local Group uncertain?
ANSWER: Answernotprovided.
126. Discuss the observational differences between spiral, elliptical, and irregular galaxies.
ANSWER: Answernotprovided.
127. Describe the kind of observations that have led astronomers to believe that
supermassive black holes lie at the centres of many galaxies.
ANSWER: Answernotprovided.
128. Our galaxy is not a radio galaxy, but it does emit radio energy. Explain where this radio
energy comes from.
ANSWER: Answernotprovided.
129. What observational evidence do we have that radio lobes are related to the ejection of
gas from galaxies?
ANSWER: Answernotprovided.
130. What observational evidence do we have that eruptions in the centres of galaxies
involve magnetic fields?
ANSWER: Answernotprovided.
131. Why should we expect quasars to be small? How small should we expect them to be?
ANSWER: Answernotprovided.
132. A quasar's redshift and apparent magnitude lead us to believe that it is very luminous.
What assumptions do we make in reaching this conclusion?
ANSWER: Answernotprovided.
133. What observational evidence do we have that quasars are the centres of very distant
galaxies?
ANSWER: Answernotprovided.
134. Describe a model of a quasar and show how the model explains the observed
properties of a quasar.
ANSWER: Answernotprovided.
135. Why are there few quasars at low redshifts and at high redshifts, but many at redshifts
of about 2?
ANSWER: Answernotprovided.
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136. What evidence do we have that active galaxies are powered by black holes at their
centres? ANSWER: Answernotprovided.
137. Describe how the effect of gravitational lensing can produce multiple images of the
same quasar. ANSWER: Answernotprovided.
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