Deck 11: Light

Question 1

Both sound and light can travel in

A)a vacuum.
B)water.
C)both of these
D)none of the above

Answer 1

B

Question 2

Which have the longest wavelengths when traveling in a vacuum?

A)radio waves
B)light
C)X-rays
D)all the same

Answer 2

A

Question 3

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

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

Answer 3

C

Question 4

A sound wave and a light wave have identical

A)speeds.
B)wavelengths.
C)frequencies.
D)all of the above
E)none of the above

Question 5

Electromagnetic waves consist of

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

Question 6

Both a radio wave and light wave have identical

A)speeds.
B)wavelengths.
C)frequencies.
D)all of the above
E)none of the above

Question 7

Most of the waves in the electromagnetic spectrum are

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

Question 8

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 9

The frequency of an electromagnetic wave and the frequency of the vibrating electrons that produce it are

A)nearly the same.
B)the same.
C)quite different.

Question 10

A wave with a long wavelength has a relatively

A)low frequency.
B)high frequency.
C)both of these
D)neither

Question 11

A changing electric field induces a changing

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

Question 12

A wave with a high frequency has a relatively

A)short wavelength.
B)long wavelength.
C)both of these
D)none of the above

Question 13

If an electric charge is rapidly shaken up and down,

A)sound is emitted.
B)light is emitted.
C)electron excitation occurs.
D)an electromagnetic wave is produced.

Question 14

Which of the following occupies the smallest percentage of the electromagnetic spectrum?

A)radio waves
B)microwaves
C)visible light
D)gamma rays

Question 15

Which of these has a higher frequency than visible light?

A)radio wave
B)microwave
C)infrared wave
D)ultraviolet wave
E)all do

Question 16

Electromagnetic waves can travel in

A)a vacuum.
B)water.
C)both of these
D)none of the above

Question 17

Which travels fastest in a vacuum?

A)radio waves
B)light
C)X-rays
D)all the same

Question 18

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 19

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

A)frequency.
B)wavelength.
C)energy.
D)amplitude.
E)basic nature.

Question 20

The source of electromagnetic waves is vibrating

A)electric charges.
B)atoms.
C)molecules.
D)energy fields.

Question 21

Electrons in glass have a natural frequency in the

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

Question 22

Relative to ultraviolet waves,the wavelength of infrared waves is

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

Question 23

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

A)resonate.
B)pass the light energy along practically undiminished.
C)freely absorb and reemit most of the ultraviolet light.

Question 24

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 of molecules in the skin that becomes thermal energy.
D)are absorbed rather than reflected by the skin.
E)are the predominant waves emitted by the Sun.

Question 25

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

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

Question 26

Non-reflected ultraviolet light that shines on a pane of transparent glass

A)produces a chain of absorptions and re-emissions through the glass.
B)transforms to thermal energy.
C)is mostly reflected.

Question 27

Radio waves travel

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

Question 28

Compared with the speed of light in a vacuum,the speed of light in the empty space between molecules in glass is

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

Question 29

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

A)radio.
B)light.
C)both of these
D)none of the above

Question 30

Metals are shiny because

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

Question 31

Consider light energy that is momentarily absorbed in glass and then reemitted.Relative to the absorbed light,the frequency of the reemitted light is

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

Question 32

Glass is transparent to light of frequencies that

A)match its natural frequencies.
B)are below its natural frequencies.
C)both of these
D)none of the above

Question 33

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 34

The distance between Earth and the Moon is 3.84 10⁸ m.A pulse of laser light aimed at the Moon that bounces back to Earth undergoes a round-trip time of about

A)zero seconds.
B)less than 1 second.
C)two and a half seconds.
D)three seconds.

Question 35

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 36

An electron vibrating to and fro 1000 times per second 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.

Question 37

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 38

When visible light is incident upon transparent glass,most atoms in the glass

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

Question 39

Visible light that shines on a pane of transparent glass

A)is mostly reflected.
B)produces a chain of absorptions and re-emissions through the glass.
C)mostly transforms to thermal energy.

Question 40

Compared with the photons of light that shines on glass,the emerging photons are

A)the same photons.
B)different though identical.
C)a mixture of being the same and different.

Question 41

The shortest plane mirror in which you can see your entire image is

A)half your height.
B)3/4 your height.
C)1/3 your height.
D)equal to your height.
E)dependent on your distance from the mirror.

Question 42

If you walk toward a mirror at a certain speed,the relative speed between you and your image is

A)half your speed.
B)your speed.
C)twice your speed.
D)none of the above

Question 43

Glass is opaque to light with wave frequencies that

A)match its natural frequencies.
B)are below its natural frequencies.
C)both of these
D)none of the above

Question 44

The amount of light reflected from the front surface of common window glass is about

A)4%.
B)8%.
C)40%.
D)92%.
E)96%.

Question 45

When light reflects from a polished surface,there is a change in its

A)frequency.
B)wavelength.
C)speed.
D)all of the above
E)none of the above

Question 46

The reason that a surface appears darker when wet has to do with

A)the darkness of liquids.
B)conversion of light to lower frequencies.
C)absorption of multiply-reflecting light inside the wet region.

Question 47

Which will warm up quicker in sunlight?

A)a piece of colored glass
B)a piece of clear glass
C)both the same

Question 48

Light shines on a pane of green glass and a pane of clear glass.The temperature will be higher in the

A)clear glass.
B)green glass.
C)neither

Question 49

Object and image for a plane mirror lie

A)along the same plane.
B)equal distances from the mirror.
C)at right angles to each other.
D)all of the above
E)none of the above

Question 50

A rough surface for infrared waves may be polished for

A)radio waves.
B)light waves.
C)both of these
D)neither

Question 51

The inversion of Marjorie's image in a plane mirror is actually an inversion of

A)left and right.
B)up and down.
C)front and back.
D)all of the above

Question 52

Compared to the wavelength of incident light,diffuse reflection occurs when the size of surface irregularities is

A)smaller.
B)larger.
C)about the same.

Question 53

Which becomes warmer in sunlight,sunglasses or clear reading glasses?

A)sunglasses.
B)reading glasses.
C)both of these
D)none of the above

Question 54

According to the law of reflection,the incident ray,reflected ray,and normal between them

A)lie in the same plane.
B)may or may not lie in the same plane.
C)lie in planes that are perpendicular to one another.

Question 55

When you read from a printed page,you're seeing reflected light that is

A)specular.
B)diffuse.
C)both of these
D)neither of these

Question 56

Diffuse reflection occurs when the size of surface irregularities is

A)small compared to the wavelength of the light used.
B)large compared to the wavelength of the light used.
C)either

Question 57

For a curved mirror,the law of reflection holds for

A)the mirror as with a plane mirror.
B)tiny segments that act as plane surfaces.
C)both convex and concave mirrors.
D)only convex mirrors.

Question 58

To see his full height,Blinky Bill who is 1.0 meter tall needs a mirror that is at least

A)0.33 m tall.
B)0.50 m tall.
C)0.75 m tall.
D)1 m tall.
E)depends on distance from the mirror.

Question 59

In looking at yourself in a steamy mirror you wipe just enough moisture away to barely see a full view of your face.If you move back from the mirror you'll see

A)a bit more of your face.
B)a bit less of your face.
C)the same amount of your face.

Question 60

The image seen in a plane mirror is due to

A)specular reflection.
B)diffuse reflection.
C)both of these
D)neither of these

Question 61

Standing at the shore of a still lake,the reflected view of scenery on the far side of the lake is the view you would see if you were upside down with your eye in the line of sight

A)where it presently is.
B)at the surface of the water where the light reflects.
C)directly beneath you,as far below water level as you are above.
D)close to the distant shore.
E)none of the above

Question 62

If you wish to send a beam of laser light from Earth to a space station above the atmosphere near the horizon,aim your laser

A)above your line of sight.
B)below your line of sight.
C)along your line of sight.

Question 63

Refraction causes the bottom of a swimming pool to appear

A)deeper.
B)more shallow.
C)neither

Question 64

Ninety-five percent of light incident on a mirror is reflected.How much light is reflected from three mirrors in succession?

A)81%
B)86%
C)90%
D)95%

Question 65

When light is refracted,there is a change in its

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

Question 66

Light travels faster in

A)warm air.
B)cool air.
C)a vacuum.

Question 67

When a mirror with a fixed beam on it is rotated through a certain angle,the reflected beam is rotated through an angle

A)equal to the angle of rotation.
B)twice as much.
C)four times as much.
D)none of the above

Question 68

When you look at yourself in a pocket mirror,and then hold the mirror farther away,you see

A)more of yourself.
B)less of yourself.
C)the same amount of yourself.

Question 69

Light changes direction when traveling from air into glass due to changes in light's

A)intensity.
B)wavelength.
C)frequency.
D)velocity.
E)amplitude.

Question 70

Because of refraction a fish in the water appears

A)nearer the surface.
B)deeper in the water.
C)at its actual depth.

Question 71

The Moon's reflected image in a lake often appears as a vertical column when the water is

A)perfectly still.
B)slightly rough.
C)very rough,churning with waves.

Question 72

If you wish to spear a fish with a regular spear,you should compensate for refraction and throw your spear

A)directly at the sighted fish.
B)above the sighted fish.
C)below the sighted fish.

Question 73

Because of refraction,a person standing waist deep in a swimming pool appears to have

A)shorter legs.
B)longer legs.
C)thinner legs.
D)none of the above

Question 74

A diver shines light up to the surface of a smooth pond at a 10° angle to the normal.Some light passes into the air above,and the part that reflects back into the water makes an angle to the normal of

A)less than 10°.
B)10°.
C)more than 10°.

Question 75

A beam of light emerges from water into air at an angle bent

A)towards the normal
B)away from the normal.
C)in a direction parallel to the normal.
D)in a direction perpendicular to the normal.
E)not at all.

Question 76

If you wish to spear a red fish with a red laser beam,you should compensate for refraction and aim your laser

A)directly at the sighted fish.
B)above the sighted fish.
C)below the sighted fish.

Question 77

If you wish to spear a small blue fish with a red laser beam,you should compensate for refraction and aim your laser

A)directly at the sighted fish.
B)above the sighted fish.
C)below the sighted fish.

Question 78

When a light beam emerges from water into air,the average light speed

A)increases.
B)decreases.
C)remains the same.

Question 79

Refraction results from changes in light's

A)frequency.
B)incident angles.
C)speed.
D)all of the above
E)none of the above

Question 80

Refraction occurs when light passing from one medium to another

A)changes frequency.
B)changes speed.
C)loses energy.
D)reflects inward.