Exam
Name___________________________________
MULTIPLE CHOICE.
Choose the one alternative that best completes the statement or answers the question.
1) When a planet is at conjunction, it will
A) be at the farthest position from the Sun in the sky, as seen from the Earth.
B) set at the same time as the Sun.
C) rise as the Sun is setting.
1)
2) When a planet is at superior conjunction,
A) the Earth is between the Sun and the planet.
B) the Sun is between the Earth and the planet.
C) the planet is between the Earth and the Sun.
2)
3) If you were to draw a straight line from the Sun to Mars and then watch this line as Mars moves along its orbit around the Sun, what would you see?
A) The length of the line (measured in kilometers) would be the same in all parts of Mars's orbit.
B) The area swept out by the line in 1 week would be the same in all parts of Mars's orbit.
C) The angle (measured in degrees) swept out by the line in 1 week would be the same in all parts of Mars's orbit.
4) Which of the following types of electromagnetic radiation from space are not blocked by the
Earth's atmosphere at all?
A) Infrared radiation.
B) Gamma rays.
C) Radio waves.
D) Ultraviolet radiation.
3)
4)
5) Which of the following theories is now considered to be the most likely for the formation of our
Moon?
A) Collision ejection theory, where an interplanetary collision knocked material into orbit around the Earth that eventually formed into the present day Moon.
B) Co creation theory, in which the Earth and the Moon were formed at the same time out of the same material.
C) Capture theory, in which the Earth's gravity drew the Moon into orbit around it.
5)
6) What is the composition of the atmosphere of Venus?
A) Venus doesn't have an atmosphere.
C) mostly ozone
B) mostly carbon dioxide, CO2
D) mostly nitrogen
6)
7) What is the composition of the atmosphere of Uranus?
A) mostly methane B) mostly sulfur
C) mostly carbon dioxide, CO2 D) Uranus doesn't have an atmosphere.
7)
1

8) Comets typically have two tails: one straight and the other curved.
Which is which?
A) The straight tail consists of dust, and the curved tail consists of gas.
B) The straight tail consists of gas, and the curved tail consists of dust.
C) The straight tail consists of gas and dust from the comet, and the curved tail consists of solar wind ions deflected by the comet's nucleus.
8)
9) If the majority of the craters on the Moon were caused by impacts from asteroids and meteoroids from space, why then are there so few equivalent craters from such impacts on the Earth?
A) Because geological processes and erosion by water and wind have destroyed most of the craters that have formed on Earth.
B) Because the gravitational field of the Moon attracted incoming objects and this shielded the Earth from these impacts.
C) Because the Moon was bombarded by material from a very different region of the Solar
System before it was captured by Earth's gravity.
9)
10) How does the Kuiper belt differ from the Oort cloud?
A) The Kuiper belt is spherical and extends out to about 500 AU from the Sun, whereas the
Oort cloud is in the plane of the ecliptic and extends to about 50,000 AU.
B) The Kuiper belt is spherical and extends to about 50,000 AU from the Sun, whereas the
Oort cloud is in the plane of the ecliptic and extends out to about 500 AU from the Sun.
C) The Kuiper belt is in the plane of the ecliptic and extends out to about 500 AU from the
Sun, whereas the Oort cloud is spherical and extends to about 50,000 AU.
11) The fuel of the Sun is ______, and the main products of the nuclear reactions include ______.
A) hydrogen; helium, neutrinos and gamma rays.
B) hydrogen; neutrinos and microwaves.
C) helium; neutrinos and microwaves.
D) helium; neutrinos and gamma rays.
10)
11)
12) Which of the following best describes a positron?
A) a particle with no charge and little or no mass
B) a very short wavelength photon
C) a positively charged electron
D) another name for a proton
13) A star of magnitude 1 is
A) impossible because magnitudes cannot be negative.
B) brighter than a star of magnitude + 2.
C) fainter than a star of magnitude + 2.
14) An astronomer makes a direct measurement of the brightness of a star in the nighttime sky.
What the astronomer has measured is
A) the star's temperature.
B) the star's apparent magnitude.
C) the star's absolute magnitude.
D) the star's luminosity.
12)
13)
14)
2

15) How is the absolute magnitude of a star defined?
A) It is the apparent magnitude a star would have if it were at an infinite distance.
B) It is the apparent magnitude a star would have if it were at a standard distance of 10 pc.
C) It is the total energy emitted by the star per second, measured in joules/sec or watts.
16) Which of the following stars is hottest?
A) An O star
B) A G star
C) A B star
D) An F star
E) An M star
17) A star that is cool and very luminous must have
A) a very small mass.
B) a very low velocity.
C) a very small radius.
D) a very large radius.
E) a very great distance from Earth.
18) In what part of the H R diagram do white dwarfs lie?
A) lower right
B) just above the Sun on the main sequence
C) upper left
D) lower left center
E) upper right
19) What is the lowest mass that a star can have on the main sequence?
A) 0.4
solar masses.
B) There is no lower limit.
C) 2.0
solar masses.
D) 0.003
solar masses.
E) 0.08
solar masses.
20) What is the source of energy that enables a main sequence star to shine?
A) Fusion of hydrogen in a shell surrounding the core.
B) Burning of gases on its surface.
C) Fusion of hydrogen in its core.
D) Fusion of helium in its core.
E) Friction between its atoms.
15)
16)
17)
18)
19)
20)
3

21) A brown dwarf is primarily composed of
A) hydrogen.
B) iron.
C) neutrons.
D) cosmic rays.
E) carbon and oxygen.
22) A white dwarf is primarily composed of
A) cosmic rays.
B) iron.
C) hydrogen and helium.
D) neutrons.
E) carbon and oxygen.
21)
22)
SHORT ANSWER.
Write the word or phrase that best completes each statement or answers the question.
23) Which planet has the warmest temperatures?
23)
24) Name the four Galilean moons of Jupiter.
24)
ESSAY.
Write your answer in the space provided or on a separate sheet of paper.
25) Draw an H R diagram and label the axes appropriately.
Sketch and describe the evolutionary path of the
Sun.
26) What will happen to the Sun in about 5 billion years?
Describe the appearance of the Sun and the processes inside the Sun to cause any changes in appearance.
27) What is the helium flash and what causes it?
28) What are neutrinos?
Describe the properties of neutrinos: mass, size, electrical charge, how they interact.
Also describe where they come from.
29) If the Sun were suddenly to be compressed to such a small size that it became a black hole (but with the same amount of mass, only in a smaller size), how would the Earth's orbit be affected?
30) What is a planetary nebula and how does it form?
4

Answer Key
Testname: AF08_PHYS185_SAMPLEFINAL
1) B
2) B
3) B
4) C
5) A
6) B
7) A
8) B
9) A
10) C
11) A
12) C
13) B
14) B
15) B
26)
27)
28)
29)
30)
16) A
17) D
18) D
19) E
20) C
21) A
22) E
23) Venus
24)
Io, Europa, Ganymede, Callista
25)
5