Roger Freedman • Robert Geller • William Kaufmann III
Universe
Tenth Edition
Clicker Questions
Chapter 6
Optics and Telescopes
When light is incident on a surface, refraction occurs
when
A. it “bounces off” at an angle (measured from the
normal) equal to the incident angle.
B. it enters the second medium and changes direction.
C. it enters the second medium and changes frequency.
D. it “bounces off” and changes frequency.
E. it “bounces off” at an angle (measured from the
normal) greater than the incident angle.
Q6.1
When light is incident on a surface, refraction occurs
when
A. it “bounces off” at an angle (measured from the
normal) equal to the incident angle.
B. it enters the second medium and changes direction.
C. it enters the second medium and changes frequency.
D. it “bounces off” and changes frequency.
E. it “bounces off” at an angle (measured from the
normal) greater than the incident angle.
A6.1
The primary purpose of building larger optical telescopes
on the Earth’s surface is to
A. increase the light-gathering power.
B. increase the magnification.
C. improve the resolution.
D. allow a wider range of wavelengths to be viewed.
E. see through the Earth’s atmosphere.
Q6.2
The primary purpose of building larger optical telescopes
on the Earth’s surface is to
A. increase the light-gathering power.
B. increase the magnification.
C. improve the resolution.
D. allow a wider range of wavelengths to be viewed.
E. see through the Earth’s atmosphere.
A6.2
What type of reflecting telescope is shown in this photo?
A. Cassegrain
B. Coudé
C. Schmidt
D. Newtonian
E. Freedman
Q6.3
What type of reflecting telescope is shown in this photo?
A. Cassegrain
B. Coudé
C. Schmidt
D. Newtonian
E. Freedman
A6.3
The light-gathering power of a 6-m reflector telescope is
bigger than for a 2-m reflector telescope by a factor of
A. 2×.
B. 3×.
C. 4×.
D. 6×.
E. 9×.
Q6.4
The light-gathering power of a 6-m reflector telescope is
bigger than for a 2-m reflector telescope by a factor of
A. 2×.
B. 3×.
C. 4×.
D. 6×.
E. 9×.
A6.4
The focal length of the objective of a refractor telescope
is 80 cm, and the focal length of the eyepiece is 8 cm.
What is the magnification of the telescope?
A. 640×
B. 80×
C. 10×
D. 8×
E. 2×
Q6.5
The focal length of the objective of a refractor telescope
is 80 cm, and the focal length of the eyepiece is 8 cm.
What is the magnification of the telescope?
A. 640×
B. 80×
C. 10×
D. 8×
E. 2×
A6.5
Chromatic aberration occurs when light
A. passes through glass.
B. reflects off glass.
C. reflects off a mirror.
D. enters a telescope just before it reflects or refracts.
E. passes through a vacuum.
Q6.6
Chromatic aberration occurs when light
A. passes through glass.
B. reflects off glass.
C. reflects off a mirror.
D. enters a telescope just before it reflects or refracts.
E. passes through a vacuum.
A6.6
Which of the following is an advantage of reflector
telescopes over refractor telescopes?
A. The objective mirror is lighter and is supported at the back and so
distortion of the objective is minimized.
B. The objective mirror produces no significant chromatic aberration.
C. There are no significant problems with light absorption in glass
because the light does not pass through a large thickness of glass.
D. A, B, and C are all advantages.
E. Only B and C are advantages.
Q6.7
Which of the following is an advantage of reflector
telescopes over refractor telescopes?
A. The objective mirror is lighter and is supported at the back and so
distortion of the objective is minimized.
B. The objective mirror produces no significant chromatic aberration.
C. There are no significant problems with light absorption in glass
because the light does not pass through a large thickness of glass.
D. A, B, and C are all advantages.
E. Only B and C are advantages.
A6.7
Why do the Keck telescopes and Very Large Telescopes
(VLT) operate with improved resolution compared to
older reflector telescopes?
A. They have a new ultrathin objective lens made of
very dense glass.
B. They are placed in Earth orbit, above the distorting
effects of the Earth’s atmosphere.
C. Their flexible mirrors prevent chromatic aberration.
D. They use adaptive optics.
E. They are built from high-impact, non-interference
producing plastics.
Q6.8
Why do the Keck telescopes and Very Large Telescopes
(VLT) operate with improved resolution compared to
older reflector telescopes?
A. They have a new ultrathin objective lens made of
very dense glass.
B. They are placed in Earth orbit, above the distorting
effects of the Earth’s atmosphere.
C. Their flexible mirrors prevent chromatic aberration.
D. They use adaptive optics.
E. They are built from high-impact, non-interference
producing plastics.
A6.8
The telescope shown in this photo is used to observe
astronomical objects in the
A. visual part of the spectrum.
B. radio part of the spectrum.
C. near-ultraviolet part of the spectrum.
D. near-infrared part of the spectrum.
E. A, C, and D are all correct.
Q6.9
The telescope shown in this photo is used to observe
astronomical objects in the
A. visual part of the spectrum.
B. radio part of the spectrum.
C. near-ultraviolet part of the spectrum.
D. near-infrared part of the spectrum.
E. A, C, and D are all correct.
A6.9
Why was the Hubble Space Telescope placed in orbit?
A. Maintenance on the telescope is easier to do in
Earth orbit than on the Earth’s surface.
B. To be closer to the stars.
C. To eliminate the distorting effect of the Earth’s
atmosphere.
D. To detect X-rays, which cannot penetrate the
Earth’s atmosphere.
E. To get away from human-generated
electromagnetic interference.
Q6.10
Why was the Hubble Space Telescope placed in orbit?
A. Maintenance on the telescope is easier to do in
Earth orbit than on the Earth’s surface.
B. To be closer to the stars.
C. To eliminate the distorting effect of the Earth’s
atmosphere.
D. To detect X-rays, which cannot penetrate the
Earth’s atmosphere.
E. To get away from human-generated
electromagnetic interference.
A6.10
What type of telescope is shown in this photo?
A. Radio interferometer
B. Reflector
C. Refractor
D. Multiple mirror
E. Gamma ray
Q6.11
What type of telescope is shown in this photo?
A. Radio interferometer
B. Reflector
C. Refractor
D. Multiple mirror
E. Gamma ray
A6.11
A radio telescope must distinguish between radio waves
(wavelength 0.6 m) emitted by two stars separated by 0.1
degree. What is the approximate minimum size of the
radio telescope?
A. 1.5 × 107 m
B. 1.5 × 105 m
C. 400 m
D. 6 m
E. 42 m
Q6.12
A radio telescope must distinguish between radio waves
(wavelength 0.6 m) emitted by two stars separated by 0.1
degree. What is the approximate minimum size of the
radio telescope?
A. 1.5 × 107 m
B. 1.5 × 105 m
C. 400 m
D. 6 m
E. 42 m
A6.12
The purpose of adaptive optics is to
A. compensate for atmospheric blurring by rapidly
changing the shape of the mirror.
B. compensate for sagging of the mirror by changing
the mirror shape.
C. compensate for chromatic aberration.
D. correct spherical aberration.
E. compensate for temperature changes of the mirror
by changing the mirror shape.
Q6.13
The purpose of adaptive optics is to
A. compensate for atmospheric blurring by rapidly
changing the shape of the mirror.
B. compensate for sagging of the mirror by changing
the mirror shape.
C. compensate for chromatic aberration.
D. correct spherical aberration.
E. compensate for temperature changes of the mirror
by changing the mirror shape.
A6.13
The Very Large Array consists of 27 radio telescopes
linked electronically. The main purpose of the Very Large
Array is to
A. gather as many radio waves as possible.
B. simulate a radio telescope with a large diameter so as to
improve diffraction-limited resolution.
C. allow many researchers to work on many different
projects at the same time.
D. remove the blurring effects of the Earth’s atmosphere.
E. cancel the effects of thunderstorms on the radio signal.
Q6.14
The Very Large Array consists of 27 radio telescopes
linked electronically. The main purpose of the Very Large
Array is to
A. gather as many radio waves as possible.
B. simulate a radio telescope with a large diameter so as to
improve diffraction-limited resolution.
C. allow many researchers to work on many different
projects at the same time.
D. remove the blurring effects of the Earth’s atmosphere.
E. cancel the effects of thunderstorms on the radio signal.
A6.14
The Hubble Space Telescope mirror was incorrectly
manufactured causing it to suffer from
A. sagging.
B. chromatic aberration.
C. spherical aberration.
D. presbyopia.
E. bubbles in the glass making up the lens.
Q6.15
The Hubble Space Telescope mirror was incorrectly
manufactured causing it to suffer from
A. sagging.
B. chromatic aberration.
C. spherical aberration.
D. presbyopia.
E. bubbles in the glass making up the lens.
A6.15
The two kinds of electromagnetic radiation that can
easily be observed through the Earth’s atmosphere are
A. visible (optical) and ultraviolet.
B. visible (optical) and infrared.
C. ultraviolet and infrared.
D. visible (optical) and radio.
E. gamma rays and x-rays.
Q6.16
The two kinds of electromagnetic radiation that can
easily be observed through the Earth’s atmosphere are
A. visible (optical) and ultraviolet.
B. visible (optical) and infrared.
C. ultraviolet and infrared.
D. visible (optical) and radio.
E. gamma rays and x-rays.
A6.16
Gamma-ray telescopes give us information
A. on some of the least energetic events in the universe.
B. on some of the most energetic events in the universe.
C. only on events at extremely large (>10 megaparsec)
distances.
D. on planetary atmospheres.
E. only on cool objects that do not emit visible light.
Q6.17
Gamma-ray telescopes give us information
A. on some of the least energetic events in the universe.
B. on some of the most energetic events in the universe.
C. only on events at extremely large (>10 megaparsec)
distances.
D. on planetary atmospheres.
E. only on cool objects that do not emit visible light.
A6.17