Question 1

The two Keck 10-m telescopes,separated by a distance of 85 m,can operate as an interferometer.What is its resolution when it observes in the infrared at a wavelength of 2 microns?

Accepted Answer

A)   0.01 arcsec
B)   0.006 arcsec
C)   0.05 arcsec
D)   0.2 arcsecE) B) and D)
F) All of the above

Question 2

Light with a wavelength of 600 nm has a frequency of:

Accepted Answer

A)   5.0 × 106 Hz
B)   5.0 × 1014 Hz
C)   5.0 × 1011 Hz
D)   2.0 × 1015 HzE) B) and C)
F) A) and D)

Question 3

The image below shows the Very Large Array in New Mexico.What is the benefit of using multiple telescopes in such an array?

Accepted Answer

Interferometry allows astronom...

Question 4

A spaceship approaches Earth at 0.9 times the speed of light and shines a powerful searchlight onto Earth.How fast will the photons from this searchlight be moving when they hit Earth?

Accepted Answer

At the spe...

Question 5

Discuss two tools that modern astronomers use to explore the cosmos that are different from traditional optical telescopes,and give an example of how and why each is used.

Accepted Answer

Here are some possible answers: (1)Radio...

Question 6

The speed of light was first determined by which scientist?

Accepted Answer

A)   Galileo
B)   Rømer
C)   Kepler
D)   Newton
E)   EinsteinF) A) and B)
G) B) and E)

Question 7

Moving charges produce magnetic fields.

Accepted Answer

A) True 
 B)False  True

Question 8

Which formula denotes how the speed of light is related to its wavelength and frequency?

Accepted Answer

A)   c =  λ\lambdaλ f
B)   c =  λ\lambdaλ /f
C)   c = f/ λ\lambdaλ 
D)   c = 1/ λ\lambdaλ f E) C) and D)
F) B) and D)

Question 9

One reason to prefer a reflecting over a refracting telescope is its:

Accepted Answer

A)   lack of chromatic aberration.
B)   shorter length for the same aperture size.
C)   lighter weight for larger apertures.
D)   All of the above are valid reasons.E) B) and D)
F) B) and C)

Question 10

A radio photon travels more slowly than a gamma ray photon.

Accepted Answer

A) True 
 B)False

Question 11

The fact that the speed of light is constant (as it travels through a vacuum) means that:

Accepted Answer

A)   photons with longer wavelengths have lower frequencies
B)   radio wave photons have shorter wavelengths than gamma ray photons
C)   X-rays can be transmitted through the atmosphere around the world
D)   All of the above are trueE) A) and D)
F) A) and C)

Question 12

Chromatic aberration is a problem that limits the image quality of reflecting telescopes.

Accepted Answer

A) True 
 B)False

Question 13

Compare the light-gathering power of the human eye to that of a 10-inch telescope.

Accepted Answer

Light-gathering power is proportional to...

Question 14

One of the reasons why the Hubble Space Telescope has better spatial resolution than a 4-m ground-based telescope is that it has a larger mirror.

Accepted Answer

A) True 
 B)False  False

Question 15

How does the speed of light traveling through a medium (such as air or glass) compare to the speed of light in a vacuum?

Accepted Answer

A)   It is the same as the speed of light in a vacuum.
B)   It is always less than the speed of light in a vacuum.
C)   It is always greater than the speed of light in a vacuum.
D)   Sometimes it is greater than the speed of light in a vacuum,and sometimes it is less,depending on the medium.E) A) and B)
F) None of the above

Question 16

Photography provides an improvement over naked-eye observations because:

Accepted Answer

A)   it is possible to observe a larger field of view with photographic plates
B)   the quantum efficiency is higher for photographic plates
C)   the image resolution is much better for photographic plates
D)   it is possible to detect fainter objects with the use of photographic platesE) B) and C)
F) A) and D)

Question 17

The 305-m Arecibo radio telescope in Puerto Rico has a resolution that is closest to that of:

Accepted Answer

A)   the Hubble Space Telescope (0.1 arcsec) 
B)   a human eye (1 arcmin) 
C)   the Chandra X-ray Telescope (0.5 arcsec) 
D)   a 1-m optical telescope (1 arcsec) E) None of the above
F) B) and D)

Question 18

As wavelength increases,the energy of a photon __________ and its frequency __________.

Accepted Answer

A)   increases; decreases
B)   increases; increases
C)   decreases; decreases
D)   decreases; increasesE) A) and B)
F) A) and C)

Question 19

The diffraction limit of a 4-m telescope is __________ than that of a 2-m telescope.

Accepted Answer

A)   2 times larger
B)   4 times larger
C)   2 times smaller
D)   4 times smallerE) B) and D)
F) None of the above

Question 20

As a beam of light travels from one medium to another,the change in direction of the beam of light depends on:

Accepted Answer

A)   the wavelength of the light
B)   the index of refraction of the medium through which it is traveling
C)   the index of refraction of the medium into which it is moving
D)   all of the aboveE) A) and D)
F) B) and C) D

Exam 4: Light and Telescopes

The two Keck 10-m telescopes,separated by a distance of 85 m,can operate as an interferometer.What is its resolution when it observes in the infrared at a wavelength of 2 microns?

Correct AnswerverifiedShow Answer

Light with a wavelength of 600 nm has a frequency of:

Correct AnswerverifiedShow Answer

The image below shows the Very Large Array in New Mexico.What is the benefit of using multiple telescopes in such an array?

Correct AnswerverifiedInterferometry allows astronom...View AnswerShow Answer

A spaceship approaches Earth at 0.9 times the speed of light and shines a powerful searchlight onto Earth.How fast will the photons from this searchlight be moving when they hit Earth?

Correct AnswerverifiedAt the spe...View AnswerShow Answer

Discuss two tools that modern astronomers use to explore the cosmos that are different from traditional optical telescopes,and give an example of how and why each is used.

Correct AnswerverifiedHere are some possible answers: (1)Radio...View AnswerShow Answer

The speed of light was first determined by which scientist?

Correct AnswerverifiedShow Answer

Moving charges produce magnetic fields.

Correct AnswerverifiedTrue

Which formula denotes how the speed of light is related to its wavelength and frequency?

Correct AnswerverifiedShow Answer

One reason to prefer a reflecting over a refracting telescope is its:

Correct AnswerverifiedShow Answer

A radio photon travels more slowly than a gamma ray photon.

Correct AnswerverifiedShow Answer

The fact that the speed of light is constant (as it travels through a vacuum) means that:

Correct AnswerverifiedShow Answer

Chromatic aberration is a problem that limits the image quality of reflecting telescopes.

Correct AnswerverifiedShow Answer

Compare the light-gathering power of the human eye to that of a 10-inch telescope.

Correct AnswerverifiedLight-gathering power is proportional to...View AnswerShow Answer

One of the reasons why the Hubble Space Telescope has better spatial resolution than a 4-m ground-based telescope is that it has a larger mirror.

Correct AnswerverifiedFalse

How does the speed of light traveling through a medium (such as air or glass) compare to the speed of light in a vacuum?

Correct AnswerverifiedShow Answer

Photography provides an improvement over naked-eye observations because:

Correct AnswerverifiedShow Answer

The 305-m Arecibo radio telescope in Puerto Rico has a resolution that is closest to that of:

Correct AnswerverifiedShow Answer

As wavelength increases,the energy of a photon __________ and its frequency __________.

Correct AnswerverifiedShow Answer

The diffraction limit of a 4-m telescope is __________ than that of a 2-m telescope.

Correct AnswerverifiedShow Answer

As a beam of light travels from one medium to another,the change in direction of the beam of light depends on:

Correct AnswerverifiedD

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Interferometry allows astronom...
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At the spe...
View Answer

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Here are some possible answers: (1)Radio...
View Answer

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True

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Light-gathering power is proportional to...
View Answer

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False

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As wavelength increases,the energy of a photon and its frequency .

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D