Question 1

In the quantum mechanical view of the atom, an electron is best thought of as:

Accepted Answer

A)  a cloud that is centered on the nucleus 
B)  a particle orbiting the nucleus 
C)  free to orbit at any distance from the nucleus 
D)  a particle inside the nucleus 
E)  All of the above are true. 
A)  a cloud that is centered on the nucleus 
B)  a particle orbiting the nucleus 
C)  free to orbit at any distance from the nucleus 
D)  a particle inside the nucleus 
E)  All of the above are true. A

Question 2

If a star has a peak wavelength of 290 nm, what is its surface temperature?

Accepted Answer

A)  1000 K 
B)  2000 K 
C)  5000 K 
D)  10,000 K 
E)  100,000 K 
A)  1000 K 
B)  2000 K 
C)  5000 K 
D)  10,000 K 
E)  100,000 K D

Question 3

A black car left in the sunlight becomes hotter than a white car left in the sunlight under the same conditions because:

Accepted Answer

A)  the white car absorbs more sunlight than the black car 
B)  the white car reflects more sunlight than the black car 
C)  the black car absorbs only blue photons and reflects red photons, whereas the white car absorbs only red photons and reflects blue photons 
D)  the atoms in the black car are smaller than the atoms in the white car 
A)  the white car absorbs more sunlight than the black car 
B)  the white car reflects more sunlight than the black car 
C)  the black car absorbs only blue photons and reflects red photons, whereas the white car absorbs only red photons and reflects blue photons 
D)  the atoms in the black car are smaller than the atoms in the white car B

Question 4

Which of these planets would be expected to have the highest average temperature?

Accepted Answer

A)  a light-colored planet close to the Sun 
B)  a dark-colored planet close to the Sun 
C)  a light-colored planet far from the Sun 
D)  a dark-colored planet far from the Sun 
E)  There is not enough information to know which would be hotter. 
A)  a light-colored planet close to the Sun 
B)  a dark-colored planet close to the Sun 
C)  a light-colored planet far from the Sun 
D)  a dark-colored planet far from the Sun 
E)  There is not enough information to know which would be hotter.

Question 5

At what temperature does water freeze?

Accepted Answer

A)  0 K 
B)  32 K 
C)  100 K 
D)  273 K 
E)  373 K 
A)  0 K 
B)  32 K 
C)  100 K 
D)  273 K 
E)  373 K

Question 6

A spaceship is traveling toward Earth while giving off a constant radio signal with a wavelength of 1 meter. What will the signal look like to people on Earth?

Accepted Answer

A)  a signal with a wavelength less than 1 m 
B)  a signal with a wavelength more than 1 m 
C)  a signal moving faster than the speed of light 
D)  a signal moving slower than the speed of light 
E)  a signal with a wavelength of 1 m, moving the normal speed of light 
A)  a signal with a wavelength less than 1 m 
B)  a signal with a wavelength more than 1 m 
C)  a signal moving faster than the speed of light 
D)  a signal moving slower than the speed of light 
E)  a signal with a wavelength of 1 m, moving the normal speed of light

Question 7

The figure below shows an energy level diagram for a hydrogen atom, with the electron in the n = 4 level.   If this atom emitted a photon, what energies could this photon have?

Accepted Answer

To emit a photon, the electron needs to

Question 8

Which of the following lists different types of electromagnetic radiation in order from the smallest wavelength to the largest wavelength?

Accepted Answer

A)  radio waves, infrared, visible, ultraviolet, X-rays 
B)  gamma rays, ultraviolet, visible, infrared, radio waves 
C)  gamma rays, X-rays, infrared, visible, ultraviolet 
D)  X-rays, infrared, visible, ultraviolet, radio waves 
E)  radio waves, ultraviolet, visible, infrared, gamma rays 
A)  radio waves, infrared, visible, ultraviolet, X-rays 
B)  gamma rays, ultraviolet, visible, infrared, radio waves 
C)  gamma rays, X-rays, infrared, visible, ultraviolet 
D)  X-rays, infrared, visible, ultraviolet, radio waves 
E)  radio waves, ultraviolet, visible, infrared, gamma rays

Question 9

Consider an incandescent light bulb. If you wanted to turn a 10 W light bulb into a 100 W light bulb, how would you change the temperature of the filament inside the bulb?

Accepted Answer

A)  Raise its temperature by a factor of 3.2. 
B)  Raise its temperature by a factor of 1.8. 
C)  Raise its temperature by a factor of 10. 
D)  Lower its temperature by a factor of 2.6. 
E)  Lower its temperature by a factor of 5.4. 
A)  Raise its temperature by a factor of 3.2. 
B)  Raise its temperature by a factor of 1.8. 
C)  Raise its temperature by a factor of 10. 
D)  Lower its temperature by a factor of 2.6. 
E)  Lower its temperature by a factor of 5.4.

Question 10

If an object is moving toward you, the light you see from it will be blueshifted.

Accepted Answer

A) True 
 B)False

Question 11

What would you expect the temperature of a comet to be if its distance was 100 AU from the Sun? Assume that it is very icy and reflective so that its albedo is equal to 0.6. Does it matter what the radius of the comet is?

Accepted Answer

No, it does not matter what the radius o

Question 12

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

Question 13

A red photon has a wavelength of 650 nm. An ultraviolet photon has a wavelength of 250 nm. The energy of an ultraviolet photon is _________ the energy of a red photon.

Accepted Answer

A)  2.6 times larger than 
B)  6.8 times larger than 
C)  2.6 times smaller than 
D)  6.8 times smaller than 
E)  the same as 
A)  2.6 times larger than 
B)  6.8 times larger than 
C)  2.6 times smaller than 
D)  6.8 times smaller than 
E)  the same as

Question 14

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

Question 15

If you observe an isolated hot cloud of gas, you will see:

Accepted Answer

A)  an absorption spectrum 
B)  a continuous spectrum 
C)  an emission spectrum 
D)  a rainbow spectrum 
E)  a dark spectrum 
A)  an absorption spectrum 
B)  a continuous spectrum 
C)  an emission spectrum 
D)  a rainbow spectrum 
E)  a dark spectrum

Question 16

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)  ultraviolet photons have less energy than visible photons 
E)  all of the above are true 
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)  ultraviolet photons have less energy than visible photons 
E)  all of the above are true

Question 17

Suppose you observe a star emitting a certain emission line of helium at 584.8 nm. The rest wavelength of this line is 587.6 nm. How fast is the star moving? Is it moving toward you or away from you?

Accepted Answer

The Doppler formula states that the radi

Question 18

You record the spectrum of a star and find that a calcium absorption line has an observed wavelength of 394.0 nm. This calcium absorption line has a rest wavelength is 393.3 nm; what is the radial velocity of this star?

Accepted Answer

A)  5,000 km/s 
B)  500 km/s 
C)  50 km/s 
D)  5 km/s 
E)  0.5 km/s 
A)  5,000 km/s 
B)  500 km/s 
C)  50 km/s 
D)  5 km/s 
E)  0.5 km/s

Question 19

How much would you have to change the temperature of an object if you wanted to increase its flux by a factor of 100?

Accepted Answer

Because flux is proportional t

Question 20

You are driving on the freeway when a police officer records a shift of -7 nm when he or she hits you with a radar gun that operates at a wavelength of 0.1 m. How fast were you going?

Accepted Answer

A)  43 mph 
B)  83 mph 
C)  21 mph 
D)  65 mph 
E)  47 mph 
A)  43 mph 
B)  83 mph 
C)  21 mph 
D)  65 mph 
E)  47 mph

Exam 5: Light

In the quantum mechanical view of the atom, an electron is best thought of as:

If a star has a peak wavelength of 290 nm, what is its surface temperature?

A black car left in the sunlight becomes hotter than a white car left in the sunlight under the same conditions because:

Which of these planets would be expected to have the highest average temperature?

At what temperature does water freeze?

A spaceship is traveling toward Earth while giving off a constant radio signal with a wavelength of 1 meter. What will the signal look like to people on Earth?

The figure below shows an energy level diagram for a hydrogen atom, with the electron in the n = 4 level. If this atom emitted a photon, what energies could this photon have?

Which of the following lists different types of electromagnetic radiation in order from the smallest wavelength to the largest wavelength?

Consider an incandescent light bulb. If you wanted to turn a 10 W light bulb into a 100 W light bulb, how would you change the temperature of the filament inside the bulb?

If an object is moving toward you, the light you see from it will be blueshifted.

What would you expect the temperature of a comet to be if its distance was 100 AU from the Sun? Assume that it is very icy and reflective so that its albedo is equal to 0.6. Does it matter what the radius of the comet is?

The speed of light in a vacuum is:

A red photon has a wavelength of 650 nm. An ultraviolet photon has a wavelength of 250 nm. The energy of an ultraviolet photon is _________ the energy of a red photon.

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

If you observe an isolated hot cloud of gas, you will see:

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

Suppose you observe a star emitting a certain emission line of helium at 584.8 nm. The rest wavelength of this line is 587.6 nm. How fast is the star moving? Is it moving toward you or away from you?

You record the spectrum of a star and find that a calcium absorption line has an observed wavelength of 394.0 nm. This calcium absorption line has a rest wavelength is 393.3 nm; what is the radial velocity of this star?

How much would you have to change the temperature of an object if you wanted to increase its flux by a factor of 100?

You are driving on the freeway when a police officer records a shift of -7 nm when he or she hits you with a radar gun that operates at a wavelength of 0.1 m. How fast were you going?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

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