Question 1

Where should telescopes purposed to observe the high energy light from the death of stars be located?

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Question 2

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?

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Question 3

Using the figure below,list the different types of electromagnetic waves in order of increasing wavelength.

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Question 4

The angular resolution of a ground-based telescope is usually set by:

Accepted Answer

A)  diffraction. 
B)  refraction. 
C)  the focal length. 
D)  atmospheric seeing.

Question 5

The speed of light was first determined by which scientist?

Accepted Answer

A)  Galileo 
B)  Rømer 
C)  Kepler 
D)  Newton 
E)  Einstein

Question 6

Give an explanation as to why electromagnetic radiation does not require a medium for propagation.

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Question 7

What type of telescope is shown in the image below?

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Question 8

The SETI project's Allen Telescope Array will have 350 radio dishes,each with an individual diameter of 6 meters,spread out over a circle whose diameter is 1 km.What would this array's spatial resolution be when it operates at 5 cm?

Accepted Answer

A)  10 arcsec 
B)  0.10 arcsec 
C)  10 arcmin 
D)  1.0 arcmin

Question 9

The Voyager 1 spacecraft is currently 16.5 billion km from Earth and heading out of our Solar System.How long does it take radio messages from Voyager 1 to reach us?

Accepted Answer

A)  1.5 days 
B)  15 hours 
C)  1.5 weeks 
D)  15 minutes

Question 10

Ultraviolet radiation is hard to observe primarily because:

Accepted Answer

A)  Earth's atmosphere easily absorbs it. 
B)  no space-based telescopes operate at ultraviolet wavelengths. 
C)  only the lowest-mass stars emit ultraviolet light. 
D)  very few objects emit at ultraviolet wavelengths.

Question 11

Explain why stars twinkle when viewed from the ground.Would they twinkle if viewed from outer space?

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Question 12

If the wavelength of a beam of light were to double,how would that affect its frequency?

Accepted Answer

A)  The frequency would be four times larger. 
B)  The frequency would be two times larger. 
C)  The frequency would be two times smaller. 
D)  The frequency would be four times smaller. 
E)  There is no relationship between wavelength and frequency.

Question 13

How do the wavelength and frequency of red light compare to the wavelength and frequency of blue light?

Accepted Answer

A)  Red light has a longer wavelength and higher frequency than does blue light. 
B)  Red light has a longer wavelength and lower frequency than does blue light. 
C)  Red light has a shorter wavelength and higher frequency than does blue light. 
D)  Red light has a shorter wavelength and lower frequency than does blue light.

Question 14

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

Accepted Answer

A)  0.01 arcsec 
B)  0.005 arcsec 
C)  0.05 arcsec 
D)  0.2 arcsec

Question 15

The major advantage CCDs have over other imaging techniques is that:

Accepted Answer

A)  they have a higher quantum efficiency. 
B)  they have a linear response to light. 
C)  they yield output in digital format. 
D)  they operate at visible and near-infrared wavelengths. 
E)  All of the above are true.

Question 16

The speed of light in a vacuum is:

Accepted Answer

A)  300,000 m/s. 
B)  300,000 mph. 
C)  300,000 km/s. 
D)  300,000,000 mph. 
E)  infinite.

Question 17

The diffraction limit of a 4-meter telescope is ________ than that of a 2-meter telescope.

Accepted Answer

A)  two times larger 
B)  four times larger 
C)  two times smaller 
D)  four times smaller

Question 18

Which telescope would collect 100 times more light than a 1-meter telescope?

Accepted Answer

A)  100-meter telescope 
B)  50-meter telescope 
C)  30-meter telescope 
D)  10-meter telescope

Question 19

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.

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 above

Exam 4: Light and Telescopes