Reference no: EM131126868

Question 1: What is light?

A) Radiant energy in the form of a stream of energy particles, called quanta (sometimes called photons).

B) Radiant energy in the form of a wave of electromagnetic energy.

C) Both A and B.

D) Neither A nor B.

Question 2: Assuming that light could curve around the Earth, about how long would it take for one trip?

1/7 second (s).

1 s.

7 s.

7 m.

Question 3: What is the approximate wavelength of red light?

5 m.

7 cm.

400 nm.

700 nm.

Question 4: List the following types of electromagnetic radiation in the order short to long wavelength.

gamma rays, X rays, ultraviolet, visible light, infrared (IR), radio waves.

radio waves, IR, visible light, ultraviolet, X rays, gamma rays.

gamma rays, X rays, IR, visible light, ultraviolet, radio waves.

radio waves, ultraviolet, visible light, IR, X rays, gamma rays.

Question 5: List the following types of electromagnetic radiation from lowest to highest energy.

gamma rays, X rays, ultraviolet, visible light, IR, radio waves.

radio waves, IR, visible light, ultraviolet, X rays, gamma rays.

gamma rays, X rays, infrared, visible light, ultraviolet, radio waves

radio waves, ultraviolet, visible light, IR, X rays, gamma rays.

Question 6: According to Wien's law, a hotter object will _____ a cooler object.

appear darker than,

radiate the same intensity of wavelengths as,

radiate more strongly at shorter wavelengths than,

appear the same color as.

Question 7: What is the difference between emission and absorption in an atom?

In emission, the nucleus goes from a lower to a higher orbit.

In emission, an electron goes from a higher to a lower orbit.

In absorption, an electron goes from a higher to a lower orbit.

Both b and c.

Question 8:  What is the relationship between wavelength (λ) and frequency (ν)? ("c" is the speed of light).Question 8 options:

λν = c

λ/ν = c

ν/λ = c

λc = ν

Question 9: Which of these are effects of the Doppler shift?

When an object is moving toward us, the wavelengths of its light decrease.

When an object is moving away from us, the wavelengths of its light increase.

When an object accelerates, the wavelengths of its light become warmer.

Both a and b are correct.

Question 10: Of these gases in the Earth's atmosphere, which strongly absorbs infrared radiation?

A) water vapor.

B) nitrogen.

C) ozone.

D) both A and C

Question 11: Which gas(es) in the Earth's atmosphere strongly absorb ultraviolet radiation?

ozone (O₃) and oxygen (O₂)

nitrogen (N₂) and argon (A).

water vapor and carbon dioxide (CO₂).

none of the above.

Question 12: What type of spectrum is emitted by a heated solid object (such as the filament of an incandescent lamp)?

continuous

emission line

absorption

none of the above

Question 13: What type of spectrum is observed when the light from a hot, dense body is seen through a cooler, tenuous gas?

continuous

emission line

absorption line

none of the above

Question 14: What type of spectrum is emitted by a hot, tenuous gas?

continuous

emission line

absorption line

none of the above

Question 15: What are some of the things astronomers can learn from the spectra of astronomical objects?

Chemical composition,

Whether a gas or solid or combination, due to the type of spectrum.

How fast the objects are moving.

All of the above.

Question 16: How do astronomers calculate a telescope's light collecting area (A)? (where r = radius of the telescope's mirror or lens, and π is 3.14159).Question 16 options:

A = 2πr

A = πr²

A = 4πr²

A=4/3πr³

Question 17: Telescope A has a mirror twice the diameter of telescope B's mirror.  How does A's light-gathering power compare to B's?

A gathers 1/2 the light that B does.

A gathers twice the light that B does.

A gathers 4 times the light that B does.

A gathers 1/4th as much light as B does.

Question 18: A telescope's resolving power measures its ability to see

Fainter sources.

More distant sources.

Finer details in sources.

Larger sources.

Question 19: One way to increase the resolving power of a telescope is to

Make its mirror bigger.

Make its mirror smaller.

Replace its mirror with a lens of the same diameter.

Observe objects using longer wavelengths.

Question 20:

What causes the image of a star to twinkle or scintillate?

Irregularities in the density of layers of Earth's atmosphere, rapidly refracting the light.

The flickering fusion process in the stars.

A purely physiological reaction in the eye.

None of these answers is correct.

Question 21: What process limits a telescope's resolving power?Question 21 options:

Reflection

Refraction

Diffraction

Distraction

Question 22: What is the difference between a reflecting and a refracting telescope?

A reflecting telescope uses a lens to focus light; a refracting telescope uses a mirror.

A reflecting telescope uses a mirror to focus light; a refracting telescope uses a lens.

Both use a mirror to focus light, but a reflecting telescope uses mirrors elsewhere to bend light.

There is no difference. Refracting is an outmoded way of saying reflecting.

Question 23: Light travels ____ in water than in air

faster

slower

at the same speed

perpendicular to

Question 24: Which of the these is a reason for using mirrors rather than lenses in telescopes?

Lenses are more expensive to make than mirrors.

Most transparent materials focus light of different colors to different spots.

Lenses can only be supported by their edges, making them sag in the middle (mirrors can be supported from behind).

All of the above.

Question 25: Why use an interferometer?

 Its two widely-spaced mirrors act like one giant telescope with increased collecting area.

Its two widely-spaced mirrors act like one giant telescope with increased resolving power.

By putting one mirror above the other you can make the instrument much smaller.

It can detect light at wavelengths not available to single telescopes.

Question 26: Which of the following astronomical objects emit radiation mostly at non-visible wavelengths?

 dust clouds in space

hot gas surrounding black holes

cold interstellar gas clouds

all of the above

Question 27: Do astronomers use ground-based X-ray telescopes?

 Yes, because they can penetrate gas clouds.

No, because no astronomical objects emit x-rays.

No, because x-rays cannot get through the Earth's atmosphere.

No, because astronomers have not yet devised detectors for x-rays.

Question 28: Why does the useful resolving power of a ground-based telescope not match it's theoretical value?

 Mirrors can't be built accurately enough.

The atmosphere blurs the image, decreasing the resolving power.

Mirrors cannot collect enough light to reach their theoretical expectations.

The theoretical value can only be reached when there is a Full Moon.

Question 29: On some telescopes, actuators on the mirror change its shape to match distortions in the atmosphere.  What is this technique called?

 Actuary observing

Interferometry.

Refraction

Adaptive Optics

Question 30: Which of the following is a reason to build an observatory in space?

They are much less expensive than ground-based observatories.

They can last forever.

To avoid atmospheric blurring.

There is no good reason to build a space-based observatory.