Deck 26: Properties of Light

Question 1

A changing electric field induces a changing

A)magnetic field.
B)electromagnetic field.
C)both of these
D)neither of these

Answer 1

magnetic field.

Question 2

If the Sun were to disappear at this moment, we wouldn't know about it for

A)7 seconds, reflex time.
B)8 seconds.
C)8 minutes.
D)8 hours.

Answer 2

8 minutes.

Question 3

What is the wavelength of a 1-hertz electromagnetic wave?

A)less than 1 m
B)1 m
C)more than 1 m

Answer 3

more than 1 m

Question 4

If a light signal and a radio signal were emitted simultaneously from Alpha Centauri, the first to reach Earth would be the

A)radio signal.
B)light signal.
C)both the same time

Question 5

Compared to ultraviolet waves, the wavelength of infrared waves is

A)shorter.
B)the same.
C)longer.

Question 6

A main difference between a radio wave and a light wave is

A)wavelength.
B)frequency.
C)both of these
D)neither of these

Question 7

Your friend says that any radio wave travels appreciably faster than any sound wave.

A)agree with your friend unconditionally
B)agree with your friend for most common cases
C)disagree with your friend
D)find a new friend

Question 8

Which travels with the greatest speed in a vacuum?

A)radio waves
B)light waves
C)X-rays
D)gamma rays
E)all have the same speed

Question 9

Radio waves travel

A)always much faster than sound waves.
B)in common cases at the same speed as sound waves.
C)slower, on average, than sound waves.
D)at a speed that depends on frequency.

Question 10

Electromagnetic waves consist of

A)compressions and rarefactions of electromagnetic pulses.
B)oscillating electric and magnetic fields.
C)particles of light energy.
D)high-frequency sound waves.

Question 11

Which of these electromagnetic waves have the longest wavelength?

A)radio waves
B)infrared waves
C)X-rays
D)ultraviolet waves
E)light waves

Question 12

If the color spectrum ranges from red to violet, then it ranges from

A)low frequencies to high frequencies.
B)long wavelengths to short wavelengths.
C)both of these
D)neither of these

Question 13

Most of the waves in the electromagnetic spectrum are

A)red light.
B)blue light.
C)green light.
D)invisible.

Question 14

In free space, electromagnetic waves travel at a

A)variety of speeds.
B)single speed.
C)speed depending on frequency.

Question 15

Compared to radio waves, the velocity of visible light waves in a vacuum is

A)less.
B)more.
C)the same.

Question 16

The source of all electromagnetic waves is

A)changes in atomic energy levels.
B)vibrating atoms and molecules.
C)accelerating electric charges.
D)crystalline fluctuations.
E)none of the above

Question 17

Compared to ultraviolet waves, the frequency of infrared waves is

A)lower.
B)the same.
C)higher.

Question 18

Which of the following is fundamentally different from the others?

A)sound waves
B)X-rays
C)gamma rays
D)light waves
E)radio waves

Question 19

Which of these electromagnetic waves have the shortest wavelength?

A)radio waves
B)infrared waves
C)X-rays
D)ultraviolet waves
E)light waves

Question 20

The fact that light travels only at 300,000 km/s in free space is a consequence of

A)electromagnetic wave propagation.
B)electromagnetic field induction.
C)Maxwell's laws.
D)energy conservation.
E)none of the above

Question 21

If an electric charge is shaken up and down frequently enough

A)sound can be emitted.
B)light can be emitted.
C)both of these
D)neither of these

Question 22

Consider light energy that is momentarily absorbed in glass and then re-emitted. Compared to the absorbed light, the frequency of the re-emitted light is

A)considerably less.
B)slightly less.
C)the same.
D)slightly more.
E)considerably more.

Question 23

The fact that you can see stars in the nighttime sky is evidence that

A)our atmosphere is transparent to visible light.
B)light can travel in a vacuum.
C)both of these
D)neither of these

Question 24

Compared to its average speed in air, the average speed of a beam of light in glass is

A)more.
B)less.
C)the same.

Question 25

Glass is transparent to

A)infrared light.
B)visible light.
C)ultraviolet light.
D)all of the above

Question 26

Kids in elementary school get this right: Which color of light gets through red glass?

A)red
B)cyan
C)none of these

Question 27

Which best shields you from sunburn when at the beach?

A)a cloudy day
B)a sheet of glass between you and the Sun
C)frequent turning of your body
D)all of the above
E)none of the above

Question 28

Glass is transparent to wave frequencies that

A)match its natural frequencies.
B)are below its natural frequencies.
C)both of these
D)neither of these

Question 29

Sunburns are produced by

A)infrared light.
B)visible light.
C)ultraviolet light.
D)all of the above
E)none of the above

Question 30

What is the wavelength of an electromagnetic wave that has a frequency of 3 kilohertz?

A)less than 1 km
B)1 km
C)more than 1 km

Question 31

If an electron vibrates up and down 1000 times each second, it generates an electromagnetic wave having a

A)period of 1000 s.
B)speed of 1000 m/s.
C)wavelength of 1000 m.
D)frequency of 1000 Hz.
E)wavelength of 1000 km.

Question 32

Which of the following cannot travel in a vacuum?

A)a light wave
B)a sound wave
C)a radio wave
D)all can
E)none can

Question 33

When ultraviolet light is incident upon glass, atoms in the glass

A)are forced into vibration.
B)resonate.
C)pass the light energy along practically undiminished.
D)freely absorb and re-emit most of the ultraviolet light.

Question 34

A main difference between a radio wave and a sound wave is

A)frequency.
B)wavelength.
C)energy.
D)amplitude.
E)medium or no medium.

Question 35

When visible light is incident upon clear glass, atoms in the glass

A)are forced into vibration.
B)resonate.
C)convert the light energy into internal energy.

Question 36

The speed of light in the void between molecules in glass is

A)more than its speed in a vacuum.
B)the same as its speed in a vacuum.
C)less than its speed in a vacuum.

Question 37

What is the frequency of an electromagnetic wave that has a wavelength of 300,000 km?

A)less than 1 Hz
B)1 Hz
C)more than 1 Hz

Question 38

The natural frequency of the atoms in glass is in the

A)infrared part of the spectrum.
B)visible part of the spectrum.
C)ultraviolet part of the spectrum.

Question 39

Compared to the photon that enters a pane of window glass, the photon that emerges is

A)the same photon.
B)an identical but different photon.
C)an altogether different photon.
D)none of the above

Question 40

Infrared waves are often called heat waves because they

A)emanate from relatively hot sources.
B)consist of frequencies lower than those of visible light.
C)induce resonance in molecules and increase internal energy in a substance.
D)are the predominant waves emitted by the sun.

Question 41

In the periphery of our vision, we are

A)more sensitive to low frequencies than high ones.
B)insensitive to color and movement.
C)sensitive to movement, but cannot see color.
D)sensitive to both movement and color.
E)none of the above

Question 42

A solar eclipse occurs when the

A)Sun passes into Earth's shadow.
B)Moon passes into Earth's shadow.
C)the Moon's shadow is cast on Earth.
D)none of the above

Question 43

The crescent shapes of spots of light cast through openings in trees occurs with a

A)partial eclipse of the Sun.
B)total eclipse of the Sun.
C)lunar eclipse, partial or total.
D)partial lunar eclipse.

Question 44

The Moon would be at its fullest just before the time of a

A)solar eclipse.
B)lunar eclipse.
C)both of these
D)neither of these

Question 45

A pair of sunglasses and a pair of clear reading glasses are left in the sunlight. The hotter glasses will be the

A)sunglasses.
B)reading glasses.
C)both of these
D)neither of these

Question 46

The cones in the retina of the eye are

A)most densely packed at the center of vision.
B)uniformly spread along the visual field.
C)concentrated along the periphery of vision.

Question 47

Earth's atmosphere is opaque to waves that are concentrated in the

A)infrared part of the spectrum.
B)visible part of the spectrum.
C)entire electromagnetic spectrum.

Question 48

A new Moon appears in the sky just before the time of a

A)solar eclipse.
B)lunar eclipse.
C)both of these
D)neither of these

Question 49

A partial solar eclipse occurs for people in the Sun's

A)umbra.
B)penumbra.
C)none of these

Question 50

While Earth is experiencing a total solar eclipse, an observer on the side of the Moon facing Earth would see

A)Earth disappear from the sky.
B)Earth dim and turn reddish.
C)nothing unusual.
D)a dark area moving across the face of Earth.

Question 51

Red-hot and blue-hot stars appear white to the eye because

A)the eye has difficulty seeing color at night.
B)they are too dim to fire the cones.
C)they are too dim to fire the rods.
D)they are overwhelmed by the blackness of the nighttime sky.
E)eye receptivity peaks in the yellow-green part of the spectrum.

Question 52

A lunar eclipse occurs when the

A)Sun passes into Earth's shadow.
B)Moon passes into Earth's shadow.
C)Earth passes into the Sun's shadow.
D)Earth passes into the Moon's shadow.

Question 53

A total shadow is called

A)an umbra, and a partial shadow a penumbra.
B)a penumbra, and a partial shadow an umbra.
C)neither of these

Question 54

Metals are shiny because

A)they reflect 100% of incident light.
B)they are poor absorbers of light.
C)their electrons vibrate to the oscillations of any incident light.
D)none of the above

Question 55

The round spots of light on the ground beneath a tree on a sunny day are images of

A)the openings between leaves above.
B)nothing in particular.
C)the Sun.

Question 56

An annular eclipse of the Sun occurs when the Moon doesn't quite cover the Sun in the zone of totality. This means that the Moon is

A)closer than usual to Earth.
B)farther than usual from Earth.
C)none of these

Question 57

The sensation of color is seen when light falls on the eye's

A)rods.
B)cones.
C)both of these
D)neither of these

Question 58

When an astronaut on the Moon experiences a solar eclipse, observers on Earth see

A)a lunar eclipse.
B)a solar eclipse.
C)no eclipse at all.

Question 59

A total solar eclipse occurs for people in the Sun's

A)umbra.
B)penumbra.
C)none of these

Question 60

Materials generally become warmer when light is

A)absorbed by them.
B)reflected by them.
C)transmitted by them.
D)all of the above
E)none of the above

Question 61

Information-carrying nerves are connected to the retina at the

A)fovea.
B)blind spot.
C)cornea.
D)iris.
E)periphery.

Question 62

Our eyes are not very good at seeing

A)motion at our peripheries.
B)differences in brightness.
C)color in dim light.
D)all of the above
E)none of the above

Question 63

The size of the pupil of your eye depends on

A)the brightness of light in the room.
B)your mood.
C)both of these
D)neither of these

Question 64

The main difference between the retina of a human eye and that of a dog's eye is the

A)predominance of cones in a dog's retina.
B)absence of cones in a dog's retina.
C)more intricate optic nerve in a human's eye.
D)small number of cones in a human's eye.
E)none of the above

Question 65

Colors are barely seen or not at all in nighttime because moonlight

A)has almost no colors in it.
B)is too dim to activate the retina's cones.
C)photons don't have enough energy to activate the retina's cones.
D)is primarily yellow light.
E)is only semi-transparent in Earth's atmosphere.