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Unit Test 26-30

front 1

Most of the waves in the electromagnetic spectrum are

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

back 1

D) invisible.

Topic: Electromagnetic Waves

front 2

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 gravitational waves.

back 2

B) oscillating electric and magnetic fields.

Topic: Electromagnetic Waves

front 3

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

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

back 3

D) energy conservation.

Topic: Electromagnetic Wave Velocity

front 4

The source of all electromagnetic waves is

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

back 4

C) accelerating electric charges.

Topic: Electromagnetic Waves

front 5

The main difference between a radio wave and a light wave is its

A) speed.
B) wavelength.
C) frequency.
D) all of these
E) two of these

back 5

E) two of these

Topic: The Electromagnetic Spectrum

front 6

Which of these electromagnetic waves has the shortest wavelength?

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

back 6

C) X-rays

Topic: The Electromagnetic Spectrum

front 7

Compared to ultraviolet waves, the wavelength of infrared waves is

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

back 7

B) longer.

Topic: The Electromagnetic Spectrum

front 8

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

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

back 8

C) the same

Topic: The Electromagnetic Spectrum

front 9

If an electric charge is shaken up and down

A) sound is emitted.
B) light is emitted.
C) electron excitation occurs.
D) a magnetic field is created.
E) its mass decreases.

back 9

D) a magnetic field is created.

Topic: Transparent Materials

front 10

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.

back 10

D) frequency of 1000 Hz.

Topic: Transparent Materials

front 11

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

back 11

A) sound waves

Topic: Properties of Light

front 12

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.

back 12

C) ultraviolet part of the spectrum.

Topic: Transparent Materials

front 13

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.

back 13

B) resonate.

Topic: Transparent Materials

front 14

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.

back 14

A) are forced into vibration.

Topic: Transparent Materials

front 15

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.

back 15

C) the same.

Topic: Transparent Materials

front 16

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.

back 16

B) the same as its speed in a vacuum.

Topic: Transparent Materials

front 17

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.

back 17

B) less.

Topic: Transparent Materials

front 18

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 absorbed rather than reflected by the skin.
E) are the predominant waves emitted by the sun.

back 18

C) induce resonance in molecules and increase internal energy in a substance.

Topic: Transparent Materials

front 19

Materials generally become warmer when light is

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

back 19

A) absorbed by them.

Topic: Opaque Materials

front 20

Sunburns are produced by

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

back 20

A) ultraviolet light.

Topic: Opaque Materials

front 21

The Earth's atmosphere is transparent to most waves in the

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

back 21

B) visible part of the spectrum.

Topic: Opaque Materials

front 22

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.

back 22

B) moon passes into Earth's shadow.

Topic: Shadows

front 23

A solar eclipse occurs when the

A) sun passes into Earth's shadow.
B) moon passes into the Earth's shadow.
C) the moon's shadow touches Earth.

back 23

C) the moon's shadow touches Earth.

Topic: Shadows

front 24

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

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

back 24

B) penumbra

Topic: Shadows

front 25

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

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

back 25

D) a tiny dark spot move across the face of Earth.

Topic: Shadows

front 26

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

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

back 26

B) cones.

Topic: Seeing Light – The Eye

front 27

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.

back 27

A) most densely packed at the center of vision.

Topic: Seeing Light – The Eye

front 28

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.

back 28

B) they are too dim to fire the cones.

Topic: Seeing Light – The Eye

front 29

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 these

back 29

C) sensitive to movement, but cannot see color.

Topic: Seeing Light – The Eye

front 30

Information-carrying nerves are connected to the retina at

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

back 30

B) the blind spot.

Topic: Seeing Light – The Eye

front 31

The size of the pupil of your eye depends on

A) the brightness of light in the room.
B) the temperature of the room.
C) the time of day.
D) your mood.
E) two of these

back 31

E) two of these

Topic: Seeing Light – The Eye

front 32

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 would reach Earth at the same time.

back 32

C) both would reach Earth at the same time.

Topic: Electromagnetic Wave Velocity

front 33

Which of the following cannot travel in a vacuum?

A) a light wave
B) a sound wave
C) a radio wave
D) All can travel in a vacuum.
E) None can travel in a vacuum.

back 33

B) a sound wave

Topic: Electromagnetic Waves

front 34

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

A) frequencies.
B) wavelengths.
C) energies.
D) amplitudes.
E) modes of travel.

back 34

E) modes of travel.

Topic: The Electromagnetic Spectrum

front 35

If the sun were to disappear right now, we wouldn't know about it for 8 minutes because it takes 8 minutes

A) for the sun to disappear.
B) to operate receiving equipment in the dark.
C) for light to travel from the sun to the Earth.
D) all of these
E) none of these

back 35

C) for light to travel from the sun to the Earth.

Topic: Electromagnetic Wave Velocity

front 36

Glass is transparent to wave frequencies that

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

back 36

B) are below its natural frequencies.

Topic: Transparent Materials

front 37

Glass is opaque to wave frequencies that

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

back 37

A) match its natural frequencies.

Topic: Transparent Materials

front 38

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

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

back 38

A) sunglasses.

Topic: Transparent Materials, Opaque Materials

front 39

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

A) solar eclipse.
B) lunar eclipse.
C) both of these
D) none of these

back 39

B) lunar eclipse.

Topic: Shadows

front 40

What is the wavelength of an electromagnetic wave that has a frequency of 1 hertz?

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

back 40

C) more than 1 m

Topic: The Electromagnetic Spectrum

front 41

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

back 41

C) more than 1 km

Topic: The Electromagnetic Spectrum

front 42

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

back 42

B) 1 Hz

Topic: The Electromagnetic Spectrum

front 43

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) absence of cones in a human's eye.
E) none of these

back 43

B) absence of cones in a dog's retina.

Topic: Properties of Light

front 44

Things seen by moonlight usually aren't colored because moonlight

A) doesn't have very many 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) all of these
E) none of these

back 44

B) is too dim to activate the retina's cones.

Topic: Seeing Light – The Eye

front 45

At the same time an astronaut on the moon sees a solar eclipse, observers on Earth see

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

back 45

A) a lunar eclipse.

Topic: Shadows

front 46

Color depends on what characteristic of light?

A) its frequency
B) its amplitude
C) both of these

back 46

A) its frequency

Topic: Color

front 47

When the frequency of light matches the natural frequency of molecules in a material, light is

A) absorbed.
B) transmitted.
C) reflected.
D) none of these

back 47

A) absorbed.

Topic: Selective Reflection

front 48

The color of an opaque object is the same as the light that is

A) transmitted.
B) absorbed.
C) reflected.
D) all of these
E) none of these

back 48

C) reflected.

Topic: Selective Reflection

front 49

What color light is transmitted by a piece of blue glass?

A) red
B) white
C) blue
D) yellow
E) orange

back 49

C) blue

Topic: Selective Transmission

front 50

The brightest color emitted by the sun is

A) red.
B) orange.
C) yellow-green.
D) green-blue.
E) violet.

back 50

C) yellow-green.

Topic: Mixing Colored Light

front 51

The solar radiation curve is

A) a dent in the otherwise spherical sun.
B) the path taken by the sun as it travels around the Earth.
C) a plot of brightness of sunlight versus its frequency.
D) a plot of the colors of sunlight versus their frequencies.
E) a plot of light intensity versus distance from the sun.

back 51

C) a plot of brightness of sunlight versus its frequency.

Topic: Mixing Colored Light

front 52

Which will warm up quicker in sunlight?

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

back 52

A) a piece of colored glass

Topic: Selective Transmission

front 53

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 – it will be the same in each.

back 53

B) green glass.

Topic: Selective Transmission

front 54

The colored dots that make up the color on a TV screen are

A) red, blue, yellow.
B) red, blue, green.
C) yellow, blue, green.
D) magenta, cyan, yellow.
E) red, green, yellow.

back 54

B) red, blue, green.

Topic: Mixing Colored Light

front 55

If three primary colors of light are to shine on a white wall to produce a white spot, the primaries must be

A) additive.
B) subtractive.
C) multiplicative.
D) divisive.

back 55

A) additive.

Topic: Mixing Colored Light

front 56

Complementary colors are two colors that

A) look good together.
B) are additive primary colors.
C) are subtractive primary colors.
D) produce white light when added together.
E) are right for each other.

back 56

D) produce white light when added together.

Topic: Complementary Colors

front 57

The complementary color of blue is

A) red.
B) green.
C) yellow.
D) cyan.
E) magenta.

back 57

D) cyan.

Topic: Complementary Colors

front 58

Magenta light is really a mixture of

A) red and blue light.
B) red and cyan light.
C) red and yellow light.
D) yellow and green light.
E) none of these

back 58

A) red and blue light.

Topic: Complementary Colors

front 59

Colors seen on TV results from color

A) addition.
B) subtraction.
C) either of these
D) neither of these

back 59

A) addition.

Topic: Mixing Colored Light

front 60

Colors seen on the cover of our physics book result from color

A) addition.
B) subtraction.
C) either of these
D) neither of these

back 60

B) subtraction.

Topic: Mixing Colored Pigments

front 61

How many colors of ink are used to print full-color pictures?

A) one plus black
B) two plus black
C) three plus black
D) four plus black
E) six plus black

back 61

C) three plus black

Topic: Mixing Colored Pigments

front 62

Different colors of light correspond to different light

A) velocities.
B) intensities.
C) polarities.
D) frequencies.
E) none of these

back 62

D) frequencies.

Topic: Color

front 63

A mixture of red and green pigments appears

A) orange.
B) yellow.
C) magenta.
D) blue.
E) blackish brown.

back 63

E) blackish brown.

Topic: Mixing Colored Pigments

front 64

A mixture of cyan and yellow pigments appears

A) orange.
B) green.
C) magenta.
D) blue.
E) blackish brown.

back 64

B) green.

Topic: Mixing Colored Pigments

front 65

Look at a full-color picture in a magazine with a magnifying glass and you'll see that the inks used are

A) red, green, and blue.
B) red, green, blue, and black.
C) magenta, cyan, and yellow.
D) magenta, cyan, yellow, and black.
E) none of these

back 65

D) magenta, cyan, yellow, and black.

Topic: Mixing Colored Pigments

front 66

Which interacts more with sounds of relatively high frequencies?

A) large bells
B) small bells
C) both the same

back 66

B) small bells

Topic: Why the Sky is Blue

front 67

Which interacts more with light of relatively high frequencies?

A) large particles
B) small particles
C) both the same

back 67

B) small particles

Topic: Why the Sky is Blue

front 68

The sky is blue because air molecules in the sky act as tiny

A) mirrors which reflect only blue light.
B) resonators which scatter blue light.
C) sources of white light.
D) prisms.
E) none of these

back 68

B) resonators which scatter blue light.

Topic: Why the Sky is Blue

front 69

A whitish sky is evidence that the atmosphere contains

A) predominantly small particles.
B) predominantly large particles.
C) a mixture of particle sizes.
D) water vapor.
E) pollutants.

back 69

C) a mixture of particle sizes.

Topic: Why the Sky is Blue

front 70

Sunsets are red, blue jays are blue; the reason's the same:

A) scattered sunlight – nothing new.
B) pigments that reflect in the blue.
C) aerosols and all such goo.
D) no one knows, but it is true.

back 70

A) scattered sunlight – nothing new.

Topic: Why Sunsets are Red

front 71

The sky is the deepest blue

A) just before a rainstorm.
B) during a rainstorm.
C) just after a rainstorm.
D) when the air is humid.
E) just before sunset.

back 71

C) just after a rainstorm.

Topic: Why the Sky is Blue

front 72

Red sunsets are due to lower frequencies of light that

A) are scattered from larger particles in the air.
B) are refracted from larger particles in the air.
C) are reflected by clouds and relatively large particles in the air.
D) survive being scattered in the air.
E) appear reddish orange to the eye.

back 72

D) survive being scattered in the air.

Topic: Why Sunsets are Red

front 73

The sun is more likely to appear red at sunset than in the middle of the day as a result of the

A) scattering of lower frequencies by larger particles in the air.
B) longer path of air through which sunlight travels.
C) lower frequencies of light emitted late in the day by the sun.
D) pollutants emitted by humans in daylight hours.
E) absorption effects of the smaller particles in the air.

back 73

B) longer path of air through which sunlight travels.

Topic: Why Sunsets are Red

front 74

A variety of sunset colors is evidence for a variety of

A) elements in the sun.
B) apparent atmospheric thicknesses.
C) atmospheric particles.
D) atmospheric temperatures.
E) primary colors.

back 74

C) atmospheric particles.

Topic: Why Sunsets are Red

front 75

The whiteness of clouds is evidence in the clouds for a variety of

A) particle sizes.
B) molecules.
C) "seeds" upon which condensation of cloud material forms.
D) light intensities.
E) water prisms.

back 75

A) particle sizes.

Topic: Why Sunsets are Red

front 76

The greenish blue of water is evidence for the

A) reflection of greenish-blue light.
B) reflection of red light.
C) absorption of greenish-blue light.
D) absorption of red light.
E) interaction between green and blue frequencies of light.

back 76

D) absorption of red light.

Topic: Why Water is Greenish Blue

front 77

The part of the electromagnetic spectrum most absorbed by water is

A) infrared.
B) lower frequencies in the visible.
C) middle frequencies in the visible.
D) higher frequencies in the visible.
E) ultraviolet.

back 77

A) infrared.

Topic: Why Water is Greenish Blue

front 78

A red crab very deep in water, where sunlight is dim, appears

A) red.
B) orange.
C) cyan.
D) brown.
E) no color – black.

back 78

E) no color – black.

Topic: Why Water is Greenish Blue

front 79

A sheet of red paper will look black when illuminated with

A) red light.
B) yellow light.
C) magenta light.
D) cyan light.
E) none of these

back 79

D) cyan light.

Topic: Color

front 80

A blue object will appear black when illuminated with

A) blue light.
B) cyan light.
C) yellow light.
D) magenta light.
E) none of these

back 80

C) yellow light.

Topic: Color

front 81

If sunlight were green instead of white, the most comfortable color to wear on a hot day would be

A) magenta.
B) yellow.
C) green.
D) blue.
E) violet.

back 81

C) green.

Topic: Color

front 82

If sunlight were green instead of white, the most comfortable color to wear on a cold day would be

A) magenta.
B) yellow.
C) green.
D) blue.
E) violet.

back 82

A) magenta.

Topic: Color

front 83

Distant dark colored hills appear blue because that is the color of the

A) atmosphere between the observer and the hills.
B) selectively reflected light that reaches a distant observer.
C) reflected light that survives scattering.
D) sky that is reflected off the hills.

back 83

A) atmosphere between the observer and the hills.

Topic: Why Sunsets are Red

front 84

Distant snow covered hills appear yellowish because that is the color of the

A) atmosphere between the observer and the hills.
B) selectively reflected light that reaches a distant observer.
C) reflected light that survives scattering.
D) sky that is reflected off the hills.

back 84

C) reflected light that survives scattering.

Topic: Why Sunsets are Red

front 85

If molecules in the sky scattered orange light instead of blue light, sunsets would be colored

A) orange.
B) yellow.
C) green.
D) blue.
E) none of these

back 85

D) blue.

Topic: Why Sunsets are Red

front 86

If the atmosphere were about 40 times thicker, at noon the sun would appear

A) red-orange.
B) orange-green.
C) green-blue.
D) blue-violet.
E) none of these

back 86

A) red-orange.

Topic: Why the Sky is Blue

front 87

The atmosphere of Jupiter is more than 1000 km thick. From the planet's surface, the noon-day sun would appear

A) white.
B) faintly white.
C) not at all.
D) none of these

back 87

D) none of these

Topic: Why the Sky is Blue

front 88

On a planet where atmospheric gases are red, distant dark colored hills would look

A) bluish.
B) greenish.
C) yellowish.
D) reddish.
E) untinted.

back 88

D) reddish.

Topic: Why Sunsets are Red

front 89

On a planet where atmospheric gases are yellow, distant snow covered hills would look

A) bluish.
B) greenish.
C) yellowish.
D) reddish.
E) untinted.

back 89

A) bluish.

Topic: Why Sunsets are Red

front 90

The redness of the lunar eclipse is evidence for the

A) refraction of sunsets and sunrises all around the world.
B) infrared light continually emitted by the moon.
C) scattering of lower frequencies of light by the moon.
D) faintly radiating atoms in our own atmosphere when sunlight is not incident upon them.
E) dim light that is incident upon the moon by Jupiter and other planets.

back 90

A) refraction of sunsets and sunrises all around the world.

Topic: Color

front 91

Light is emitted when

A) electron clouds of atoms are forced into oscillation.
B) atomic nuclei are made to vibrate.
C) electromagnetic waves emanate from matter.
D) high-frequency sound waves strike matter.

back 91

A) electron clouds of atoms are forced into oscillation.

Topic: Reflection

front 92

Light will almost always travel from one place to another along a path of least

A) distance.
B) time.
C) effort.
D) expense.
E) complication.

back 92

B) time.

Topic: Principle of Least Time

front 93

The incident light ray, the reflected light ray, and the 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.

back 93

A) lie in the same plane.

Topic: Law of Reflection

front 94

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 these
E) none of these

back 94

B) equal distances from the mirror.

Topic: Plane Mirrors

front 95

The amount of light reflected from the front surface of a common windowpane is about

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

back 95

A) 4 percent.

Topic: Plane Mirrors

front 96

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) microscopic.

back 96

B) large compared to the wavelength of the light used.

Topic: Reflection

front 97

A surface that is considered rough for infrared waves may be polished for

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

back 97

A) radio waves.

Topic: Diffuse Reflection

front 98

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

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

back 98

E) none of these

Topic: Reflection

front 99

If you walk towards 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 these

back 99

C) twice your speed.

Topic: Reflection

front 100

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

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

back 100

A) half your height.

Topic: Reflection

front 101

To see his full height, a boy that is 1 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 how far the mirror is from the boy

back 101

B) 0.50 m tall.

Topic: Reflection

front 102

You wish to photograph the image of your little sister, who is standing 2 meters from a plane mirror. Holding the camera beside her head, you should set the distance for

A) 1 meter.
B) 2 meters.
C) 3 meters.
D) 4 meters.
E) none of these

back 102

D) 4 meters.

Topic: Plane Mirrors

front 103

A diver shines light up to the surface of a smooth pond at a 10-degree 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 degrees.
B) 10 degrees.
C) more than 10 degrees.

back 103

B) 10 degrees.

Topic: Refraction

front 104

A yellow-white candle flame reflected from a piece of red glass shows two images; one from each surface.

A) Both images are yellow-white.
B) One image is yellow-white and the other red.
C) Both images are red.
D) Both images are reddish yellow.

back 104

B) One image is yellow-white and the other red.

Topic: Reflection

front 105

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.

back 105

C) the same amount of yourself.+

Topic: Reflection

front 106

It is difficult to see the roadway in front of you when you are driving on a rainy night mainly because

A) light scatters from raindrops and cuts down the light to reach your eyes.
B) of added condensation on the inner surface of the windshield.
C) the film of water on your windshield provides an additional reflecting surface.
D) the film of water on the roadway makes the road less diffuse.
E) none of these

back 106

D) the film of water on the roadway makes the road less diffuse.

Topic: Diffuse Reflection

front 107

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 already 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 these

back 107

C) directly beneath you, as far below water level as you are above.

Topic: Reflection

front 108

Figure 28-A

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

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

back 108

B) twice as large.

Topic: Reflection

front 109

The inversion of your image in a plane mirror is actually an inversion of

A) left-right.
B) up-down.
C) front-back.
D) all of these

back 109

C) front-back.

Topic: Plane Mirrors

front 110

Figure 28-B

Reflected light from the moon 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.

back 110

B) slightly rough.

Topic: Reflection

front 111

Ninety-five percent of light incident on a mirror is reflected. How much light is reflected when three of these mirrors are arranged so light reflects from one after the other?

A) 81%
B) 85%
C) 86%
D) 90%
E) 95%

back 111

C) 86%

Topic: Reflection

front 112

Figure 28-C

Two plane mirrors are at right angles to each other. A coin placed near the mirrors has at most

A) 2 images.
B) 3 images.
C) 4 images.
D) more than 4 images.

back 112

B) 3 images.

Topic: Reflection

front 113

As a light ray enters or exits a water-air interface at an angle of 15 degrees with the normal, it

A) always bends toward the normal.
B) always bends away from the normal.
C) sometimes bends towards the normal.
D) does not bend.

back 113

A) always bends toward the normal.

Topic: Refraction

front 114

When light passes through an ordinary window pane, its angle of emergence is

A) usually less than its angle of incidence.
B) always less than its angle of incidence.
C) the same as its angle of incidence.
D) usually more than its angle of incidence.
E) always more than its angle of incidence.

back 114

C) the same as its angle of incidence.

Topic: Refraction

front 115

Light travels fastest in

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

back 115

C) a vacuum.

Topic: Refraction

front 116

Atmospheric refraction makes the daylight hours a bit

A) longer.
B) shorter.
C) longer in summer but shorter in winter.

back 116

A) longer.

Topic: Refraction

front 117

A mirage is a result of atmospheric

A) reflection.
B) refraction.
C) scattering.
D) dispersion.
E) aberrations.

back 117

B) refraction.

Topic: Refraction

front 118

The twinkling of the stars is a result of atmospheric

A) reflection.
B) refraction.
C) scattering.
D) dispersion.
E) aberrations.

back 118

B) refraction.

Topic: Refraction

front 119

Refraction results from differences in light's

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

back 119

C) speed.

Topic: Refraction

front 120

Light refracts when traveling from air into glass because light

A) has greater intensity in air than in glass.
B) has greater intensity in glass than in air.
C) has greater frequency in air than in glass.
D) has greater frequency in glass than in air.
E) travels slower in glass than in air.

back 120

E) travels slower in glass than in air.

Topic: Refraction

front 121

At night an underwater scuba diver aims his flashlight beam toward the surface at an angle of 15 degrees with the normal. Upon emerging, the beam angle will be

A) less than 15 degrees.
B) 15 degrees.
C) more than 15 degrees.
D) impossible to predict.

back 121

C) more than 15 degrees.

Topic: Refraction

front 122

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

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

back 122

A) increases.

Topic: Refraction

front 123

Refraction causes the bottom of a swimming pool to appear

A) farther down than it actually is.
B) closer to the surface than it actually is.
C) neither.

back 123

B) closer to the surface than it actually is.

Topic: Refraction

front 124

The average speed of light is greatest in

A) red glass.
B) orange glass.
C) green glass.
D) blue glass.
E) is the same in all of these

back 124

A) red glass.

Topic: Refraction

front 125

Different colors are dispersed by a prism because different colors in the prism have different

A) frequencies.
B) speeds.
C) directions.
D) energies.
E) none of these

back 125

B) speeds.

Topic: Refraction

front 126

Rainbows are not usually seen as complete circles because

A) the ground is usually in the way.
B) they are actually elliptical.
C) they have no bottom part.
D) raindrops are not perfectly round.
E) rainbows are actually arched shaped.

back 126

A) the ground is usually in the way.

Topic: Rainbows

front 127

A single raindrop illuminated by sunshine disperses

A) a single color.
B) either low-, middle-, or high-frequency colors in most cases.
C) all the colors of the rainbow.

back 127

C) all the colors of the rainbow.

Topic: Rainbows

front 128

When you view a distant rainbow, each single water drop contributes to the bow

A) a single color.
B) either low-, middle-, or high-frequency colors in most cases.
C) all the colors of the rainbow.

back 128

A) a single color.

Topic: Rainbows

front 129

The secondary rainbow is dimmer than the primary rainbow because

A) its colors are inverted.
B) it is larger, and its energy is spread over more area.
C) it is farther from the viewer.
D) it simply has much less energy than the primary bow.
E) of an extra reflection and refraction in the drops.

back 129

E) of an extra reflection and refraction in the drops.

Topic: Rainbows

front 130

The critical angle for a transparent material is the angle at and beyond which all light within the material is

A) refracted.
B) reflected.
C) absorbed.
D) dispersed.
E) diffused.

back 130

B) reflected.

Topic: Total Internal Reflection

front 131

The critical angle is least in which of the following?

A) glass
B) water
C) diamond
D) vacuum

back 131

C) diamond

Topic: Total Internal Reflection

front 132

In optical fibers of uniform density, light actually

A) curves in a direction parallel to the central axis of the fiber.
B) travels in straight-line segments.
C) travels along the outer surface of the fiber.
D) None of the above choices are correct.

back 132

B) travels in straight-line segments.

Topic: Refraction

front 133

Optical fibers are now used by

A) surgeons.
B) mechanics.
C) engineers.
D) all of these

back 133

D) all of these

Topic: Total Internal Reflection

front 134

Your image in a plane mirror is

A) virtual.
B) real.
C) both of these
D) neither of these

back 134

A) virtual.

Topic: Plane Mirrors

front 135

The type of lens that spreads parallel light is a

A) converging lens.
B) diverging lens.
C) combination converging-diverging lens.

back 135

B) diverging lens.

Topic: Lenses

front 136

Which of the following can be projected onto a viewing screen?

A) a real image
B) a virtual image
C) both
D) neither

back 136

A) a real image

Topic: Image Formation by Lens

front 137

A "burning glass" used to concentrate sunlight in a tiny spot is a

A) converging lens.
B) diverging lens.
C) either
D) neither

back 137

A) converging lens.

Topic: Lenses

front 138

The image of the "infinitely-far-away" sun produced by a converging lens appears

A) between the lens and the focal point.
B) at the focal point.
C) beyond the focal point.

back 138

B) at the focal point.

Topic: Lenses

front 139

Figure 28-D

The image in a pinhole camera is

A) always inverted.
B) sometimes inverted.
C) always right-side up.

back 139

A) always inverted.

Topic: Lenses

front 140

When the pinhole in a pinhole camera is made larger, the image is

A) brighter.
B) clearer.
C) both
D) neither

back 140

A) brighter.

Topic: Lenses

front 141

Your vision is sharpest when your pupil is

A) dilated.
B) constricted.
C) same either way.

back 141

B) constricted.

Topic: Lenses

front 142

Chromatic aberration is absent in

A) converging lenses
B) diverging lenses.
C) front surface plane mirrors.

back 142

C) front surface plane mirrors.

Topic: Lens Defects

front 143

Chromatic aberration is a consequence of different colors in a lens having different

A) aberrations.
B) frequencies.
C) energies.
D) critical angles.
E) speeds.

back 143

E) speeds.

Topic: Lens Defects

front 144

When a light ray passes at a non-90 degree angle from water into air, it

A) bends toward the normal.
B) bends away from the normal.
C) travels much slower.

back 144

B) bends away from the normal.

Topic: Refraction

front 145

Fermat's principle of least time applies to

A) reflection.
B) refraction.
C) both of these
D) neither of these

back 145

C) both of these

Topic: Principle of Least Time

front 146

Fermat's principle of least time could also be the principle of least distance for the case of

A) reflection.
B) refraction.
C) both of these
D) neither of these

back 146

A) reflection.

Topic: Principle of Least Time

front 147

A beam of light travels fastest in

A) glass.
B) water.
C) plastic.
D) air.
E) is the same in each of these

back 147

D) air.

Topic: Refraction

front 148

When seen from an airplane, a rainbow sometimes forms a complete circle. When this happens, the plane's shadow is

A) in the center of the rainbow.
B) in the lower part of the rainbow.
C) in the upper part of the rainbow.
D) totally outside the rainbow.
E) nowhere, for there is no shadow.

back 148

A) in the center of the rainbow.

Topic: Rainbows

front 149

A fish outside water will see better if it has goggles that are

A) tinted blue.
B) hemispheres.
C) filled with water.
D) extremely shiny.
E) none of these

back 149

C) filled with water.

Topic: Refraction

front 150

Which of the following are consequences of light's traveling at different speeds in different media?

A) mirages
B) rainbows
C) internal reflection
D) all of these
E) none of these

back 150

D) all of these

Topic: Rainbows, Mirages, Total Internal Reflection

front 151

Stars twinkle when seen from the Earth. When seen from the moon, stars

A) twinkle more.
B) twinkle less.
C) don't twinkle.

back 151

C) don't twinkle.

Topic: Refraction

front 152

Atmospheric refraction tends to make daytimes

A) longer.
B) shorter.
C) no change in day length

back 152

A) longer.

Topic: Refraction

front 153

If a fish looks upward at 45 degrees with respect to the water's surface, it will see

A) the bottom of the pond.
B) another fish in the pond.
C) the sky and possibly some hills.
D) only the water's surface.
E) none of these

back 153

C) the sky and possibly some hills.

Topic: Refraction

front 154

Rainbows exist because light is

A) reflected.
B) refracted.
C) both of these
D) neither of these

back 154

C) both of thes

Topic: Rainbows

front 155

A person standing waist-deep in a swimming pool appears to have short legs because of light

A) reflection.
B) absorption.
C) interference.
D) diffraction.
E) refraction.

back 155

E) refraction.

Topic: Refraction

front 156

Different colors of light travel at different speeds in a transparent medium. In a vacuum, different colors of light travel at

A) different speeds.
B) the same speed.
C) light travels at the same speed everywhere.

back 156

B) the same speed.

Topic: Refraction, Dispersion

front 157

When white light goes from air into water, the color that refracts the most is

A) red.
B) orange.
C) green.
D) violet.
E) All refract the same amount.

back 157

D) violet.

Topic: Refraction, Dispersion

front 158

The refraction of light in a diamond is greater for

A) long-wavelength light.
B) short-wavelength light.
C) Both refract the same.

back 158

B) short-wavelength light.

Topic: Refraction, Dispersion

front 159

A primary rainbow is brighter than a secondary rainbow because

A) sunlight reaching it is more intense.
B) there is one less reflection inside the water drops.
C) larger drops produce primary rainbows.
D) the secondary bow is a dim reflection of the primary rainbow.
E) none of these

back 159

B) there is one less reflection inside the water drops.

Topic: Rainbows

front 160

Figure 28-F

The sun's elliptical shape at sunset can be adequately explained by

A) Fermat's principle.
B) the law of refraction.
C) both of these
D) none of these

back 160

C) both of these

Topic: Refraction, Principle of Least Time

front 161

Objects infinitely far away are focused by a converging lens

A) in front of the focal point.
B) at the focal point.
C) beyond the focal point.

back 161

B) at the focal point.

Topic: Lenses

front 162

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

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

back 162

C) below the sighted fish.

Topic: Refraction
A lens can be used to take light emanating from a point source and bring it back to another point. This second point is called the first point's image.

front 163

Figure 28-G

From what you know about the refraction of various wavelengths of visible light, would red light and blue light from the same source produce images at the same place?

A) Yes.
B) No. Blue light would make an image closer to the lens.
C) No. Red light would make an image closer to the lens.

back 163

B) No. Blue light would make an image closer to the lens.

Topic: Refraction, Dispersion, Lenses

front 164

If you wish to hit a red fish with a red laser beam, you should compensate for refraction between the air and water by aiming your laser

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

back 164

A) directly at the sighted fish.

Topic: Refraction

front 165

If you wish to hit a blue fish with a red laser beam, you should compensate for refraction between the air and water by aiming your laser

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

back 165

C) below the sighted fish.

Topic: Refraction

front 166

If you wish to send a beam of laser light to a space station that is just above the atmosphere near the horizon, you should aim your laser

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

back 166

C) along your line of sight.+

Topic: Refraction

front 167

A person who sees more clearly under water without eyeglasses or a face mask is

A) nearsighted.
B) farsighted.
C) neither

back 167

A) nearsighted.

Topic: Refraction

front 168

A mirage occurs for surfaces that are

A) horizontal.
B) vertical.
C) both of these

back 168

C) both of these

Topic: Mirages

front 169

A mirage occurs for road surfaces that are

A) warm.
B) cold.
C) wet.
D) hard.
E) snowy.

back 169

A) warm.

Topic: Mirages

front 170

When light is refracted, there is a change in its

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

back 170

B) wavelength.

Topic: Refraction

front 171

The moon's redness during a lunar eclipse results from

A) only lower frequencies being reflected from the moon.
B) infrared radiation that is normally blocked.
C) an optical illusion.
D) refraction by the Earth's atmosphere of Earth's sunrises and sunsets.
E) none of these

back 171

D) refraction by the Earth's atmosphere of Earth's sunrises and sunsets.

Topic: Refraction

front 172

When a pulse of white light is incident on a piece of glass, strictly speaking, the first color to emerge is

A) red.
B) orange.
C) green.
D) violet.
E) They all emerge at the same time.

back 172

A) red.

Topic: Refraction

front 173

Magnification from a lens would be greater if light

A) propagated instantaneously.
B) traveled faster in glass than it does.
C) traveled slower in glass than it does.
D) beams spread out more.
E) none of these

back 173

C) traveled slower in glass than it does.

Topic: Lenses

front 174

When taking a picture of a nearby object, your camera lens should be moved

A) closer than one focal length from the film.
B) farther than one focal length from the film.
C) to one focal length from the film.

back 174

B) farther than one focal length from the film.

Topic: Lenses

front 175

Ninety percent of light incident on a certain piece of glass passes through it. How much light passes through two pieces of this glass?

A) 80%
B) 81%
C) 85%
D) 89%
E) 90%

back 175

B) 81%

Topic: Reflection

front 176

As monochromatic light passes from air to glass and back to air, changes are observed in its

A) wavelength, frequency, and speed.
B) wavelength and frequency.
C) wavelength and speed.
D) frequency and speed.
E) None of the above choices are correct.

back 176

C) wavelength and speed.

Topic: Refraction

front 177

If the speed of light in a medium is 2 × 108 m/s, the medium's index of refraction is

A) 0.50.
B) 0.67.
C) 1.0.
D) 1.5.
E) 2.0.

back 177

B) 0.67.

Topic: Refraction

front 178

According to Huygens' principle, every point on a wave

A) is a diffraction source.
B) behaves as a source of new waves.
C) is the superposition of every other part of the wave.
D) all of these
E) none of these

back 178

B) behaves as a source of new waves.

Topic: Huygens' Principle

front 179

Consider plane waves incident upon a barrier with a small opening. After passing through the opening, the waves

A) continue as plane waves.
B) fan out.
C) converge.
D) become polarized.
E) all of these

back 179

B) fan out.

Topic: Huygens' Principle

front 180

Diffraction is more pronounced through relatively

A) small openings.
B) large openings.
C) same for each

back 180

A) small openings.

Topic: Huygens' Principle

front 181

Waves diffract the most when their wavelength is

A) short.
B) long.
C) Both diffract the same.

back 181

B) long.

Topic: Diffraction

front 182

The type of radio waves that is diffracted the most around small buildings are

A) AM.
B) FM.
C) Both diffract equally.

back 182

A) AM.

Topic: Diffraction

front 183

To perceive greater detail a dolphin emits sounds of

A) lower frequency.
B) higher frequency.
C) greater intensity.
D) greater speed.
E) none of these

back 183

B) higher frequency.

Topic: Diffraction

front 184

For viewing tiny objects in a microscope, diffraction is

A) helpful.
B) a hindrance.
C) not a factor.

back 184

B) a hindrance.

Topic: Diffraction

front 185

For radio reception, diffraction is

A) helpful.
B) a hindrance.
C) not a factor.

back 185

A) helpful.

Topic: Diffraction

front 186

Diffraction is a result of

A) refraction.
B) reflection.
C) interference.
D) polarization.
E) dispersion.

back 186

C) interference.

Topic: Diffraction

front 187

Newton's rings are a demonstration of

A) refraction.
B) reflection.
C) dispersion.
D) polarization.
E) interference.

back 187

E) interference.

Topic: Interference

front 188

Interference is a property of

A) light waves.
B) sound waves.
C) water waves.
D) all of these
E) none of these

back 188

D) all of these

Topic: Interference

front 189

Colors seen when gasoline forms a thin film on water are a demonstration of

A) refraction.
B) reflection.
C) dispersion.
D) polarization.
E) interference.

back 189

E) interference.

Topic: Interference

front 190

Iridescent colors seen in the pearly luster of an abalone shell are due to

A) refraction.
B) diffraction.
C) dispersion.
D) polarization.
E) interference.

back 190

E) interference.

Topic: Interference

front 191

Polarization is a property of

A) transverse waves.
B) longitudinal waves.
C) both
D) neither

back 191

A) transverse waves.

Topic: Polarization

front 192

The vibrational direction of the electron and the plane of polarization of the light it emits

A) are the same.
B) are at right angles to each other.
C) may or may not be at right angles to each other.
D) are independent of each other.

back 192

A) are the same.

Topic: Polarization

front 193

Some double-pane airplane windows darken when the inner pane is rotated. The panes are

A) thin films.
B) Polaroid filters.
C) optical fibers.

back 193

B) Polaroid filters.

Topic: Polarization

front 194

Light will not pass through a pair of Polaroids when their axes are

A) parallel.
B) perpendicular.
C) 45 degrees to each other.
D) two of these
E) all of these

back 194

B) perpendicular.

Topic: Polarization

front 195

The glare seen from water is largely

A) horizontally polarized.
B) vertically polarized.
C) unpolarized.

back 195

A) horizontally polarized.

Topic: Polarization

front 196

The polarization axes of ordinary sunglasses are

A) vertical.
B) horizontal.
C) at right angles to each other.

back 196

A) vertical.

Topic: Polarization

front 197

The polarization axes of glasses for 3-D viewing are

A) vertical.
B) horizontal.
C) at right angles to each other.

back 197

C) at right angles to each other.

Topic: Polarization

front 198

Viewing exact duplicates of slides in the left and right positions of a stereo projector produces

A) depth.
B) no depth.

back 198

B) no depth.

Topic: Polarization

front 199

The function of polarizing filters in viewing 3-D slides or movies is to provide each eye

A) the ability to see parallax.
B) a balanced intensity.
C) an independent left or right-hand view.
D) a stereoscopic view.
E) with light polarized at right angles to each other.

back 199

C) an independent left or right-hand view.

Topic: Polarization

front 200

A property of non-cubic transparent crystals is that light travels through them

A) in mutually perpendicular directions.
B) without refracting.
C) and becomes polarized in the process.
D) at different speeds along different optic axes.
E) none of these

back 200

D) at different speeds along different optic axes.

Topic: Polarization

front 201

A property of non-cubic transparent crystals is that polarized light that travels through them
A) breaks up into two perpendicular planes.
B)
B) is depolarized.
C) is rotated.
D) slows in speed.
E) none of these

back 201

C) is rotated.

Topic: Polarization

front 202

An inventor proposes to equip an office with a polarized source of background music and let those who prefer not to hear it wear polarizing earplugs. His idea is

A) a good one – giving people a choice.
B) too expensive.
C) too much bother.
D) nonsense – you can't polarize a sound wave.

back 202

D) nonsense – you can't polarize a sound wave.

Topic: Polarization

front 203

A hologram is simply a

A) complex diffraction grating.
B) thin sheet of non-cubic transparent crystals.
C) pair of semi-crossed polarization filters.
D) thin photographic film with microscopic images over the entire surface.
E) none of these

back 203

A) complex diffraction grating.

Topic: Holography

front 204

Interference colors in a soap bubble give evidence that the soap film

A) has two reflecting surfaces.
B) is thin.
C) both of these
D) neither of these

back 204

C) both of these

Topic: Interference

front 205

Interference colors for light are analogous to

A) resonance for sound.
B) the sonic boom for sound.
C) partial tones for sound.
D) Fourier analysis for sound.
E) beats for sound.

back 205

E) beats for sound.

Topic: Interference

front 206

When long-wavelength light is seen in the interference colors of a soap bubble, the wavelength being cancelled is relatively

A) long.
B) short.
C) neither

back 206

B) short.

Topic: Interference

front 207

When you view a soap film by white light coming from almost behind your head, you see a certain color. A friend on the other side of the film likely sees

A) the same color.
B) a different color.

back 207

B) a different color.

Topic: Interference

front 208

Monochromatic light is light of a single

A) wavelength.
B) frequency.
C) color.
D) all of these
E) none of these

back 208

D) all of these

Topic: Interference

front 209

Consider the interference colors seen in a film of gasoline on a wet street. The function of the water is to provide a

A) means of spreading the gasoline into a thin film.
B) means of slowing the rapid evaporation of gasoline.
C) chemical bond with the gasoline.
D) second reflecting surface.
E) all of these

back 209

D) second reflecting surface.

Topic: Interference, Reflection

front 210

A thin film appears blue when illuminated with white light. The color being cancelled by destructive interference is

A) red.
B) green.
C) white.
D) blue.
E) none of these

back 210

E) none of these

Topic: Interference

front 211

The spacing of Newton's rings will be greater with

A) red light.
B) blue light.
C) white light.

back 211

A) red light.

Topic: Interference

front 212

Which of the following is a property of light waves, but not of sound waves?

A) frequency
B) wavelength
C) amplitude
D) polarization
E) none of these

back 212

D) polarization

Topic: Light Waves

front 213

The amount of light from an incandescent lamp that is transmitted through an ideal Polaroid filter is half, and through a real Polaroid filter is

A) less than half.
B) more than half.
C) half.

back 213

A) less than half.

Topic: Polarization

front 214

An ideal Polaroid will transmit 50% of unpolarized light incident on it. How much light is transmitted by two ideal Polaroids that are oriented with their axes parallel to each other?

A) 0%
B) 50%
C) 100%
D) between 0% and 50%
E) between 50% and 100%

back 214

B) 50%

Topic: Polarization

front 215

A painting looks less flat when viewed with

A) one eye.
B) both eyes.
C) Polaroid glasses.

back 215

A) one eye.

Topic: Three-Dimensional Viewing

front 216

Holograms employ the principle of

A) diffraction.
B) interference.
C) both of these
D) neither of these

back 216

C) both of these

Topic: Holography

front 217

Magnification can be accomplished with a hologram when viewed with light that has a

A) longer wavelength than the original light.
B) shorter wavelength than the original light.
C) Holograms cannot be magnified.

back 217

A) longer wavelength than the original light.

Topic: Holography

front 218

The spacings between double-slit interference fringes is increased if the slits are

A) closer together.
B) farther apart.
C) narrower.
D) wider.
E) none of these

back 218

A) closer together.

Topic: Interference

front 219

Interference effects are less visible for thick films because the reflected waves

A) from the bottom surface are too dim.
B) become too dispersed.
C) all end up in phase with each other.
D) are too displaced to interfere.

back 219

D) are too displaced to interfere.

Topic: Interference

front 220

Camera lenses coated with a layer of transparent material of the right thickness are almost completely non-reflective for light near the middle of the visible spectrum. They do, however, reflect a significant amount of

A) green.
B) red.
C) white.
D) violet.
E) red and violet.

back 220

E) red and violet.

Topic: Thin Films

front 221

Because of absorption, a Polaroid will actually transmit 40% of incident unpolarized light. Two such Polaroids with their axes aligned will transmit

A) 0%.
B) 40%.
C) 100%.
D) between 0% and 40%.
E) between 40% and 100%.

back 221

D) between 0% and 40%.

Topic: Polarization

front 222

Light from a lit match comes from

A) electrons.
B) protons.
C) neutrons.
D) all of these

back 222

A) electrons.

Topic: Light Emission

front 223

To say that energy levels in an atom are discrete is to say the energy levels are well defined and

A) separate from one another.
B) separated from one another by the same energy increments.
C) continuous.
D) private.

back 223

A) separate from one another.

Topic: Excitation

front 224

Electrons with the greater potential energies with respect to the atomic nucleus are

A) inner electrons.
B) outer electrons.
C) both the same, actually

back 224

B) outer electrons.

Topic: Excitation

front 225

An excited atom is an atom

A) that has excess vibration.
B) that has one or more displaced electrons.
C) with more protons than electrons.
D) that is frantic.

back 225

B) that has one or more displaced electrons.

Topic: Excitation

front 226

Light is emitted when an electron

A) is boosted to a higher energy level.
B) makes a transition to a lower energy level.
C) neither of these

back 226

B) makes a transition to a lower energy level.

Topic: Excitation

front 227

An atom that absorbs a photon of a certain energy can then emit

A) only a photon of that energy.
B) a photon of any energy.
C) only a photon of the same or higher energy.
D) only a photon of the same or lower energy.

back 227

D) only a photon of the same or lower energy.+

Topic: Excitation

front 228

A throbbing pulse of electromagnetic radiation is called a

A) proton.
B) photon.
C) lightron.
D) sparktron.
E) notron.

back 228

B) photon.

Topic: Excitation

front 229

The energy of a photon is related to

A) the energy given to the atom that emits it.
B) the energy level difference though which it falls.
C) its frequency.
D) all of these
E) none of these

back 229

D) all of these

Topic: Excitation

front 230

The highest frequency light of those below is

A) red.
B) green.
C) blue.
D) violet.
E) all the same

back 230

D) violet.

Topic: Light Emission, Ch. 26 Electromagnetic Spectrum

front 231

Which color of light carries the most energy per photon?

A) red
B) green
C) blue
D) violet
E) all the same

back 231

D) violet

Topic: Excitation

front 232

Ultraviolet light is

A) more energetic than X-rays.
B) produced by crossed Polaroids.
C) electromagnetic energy.
D) present everywhere.
E) none of these

back 232

C) electromagnetic energy.

Topic: Light Emission

front 233

Compared to the energy of a photon of red light, the energy of a photon of blue light is

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

back 233

B) more.

Topic: Light Emission

front 234

Atoms of neon in a glass tube can be excited

A) once per atom.
B) over and over again.

back 234

B) over and over again.

Topic: Excitation

front 235

The variety of colors seen in a burning log comes from the variety of

A) multi-layered incandescent surfaces.
B) electron transitions in various atoms.
C) temperatures.
D) chemicals in the log.
E) absorbing gases between the log and the viewer.

back 235

B) electron transitions in various atoms.

Topic: Excitation

front 236

Fluorescent minerals on display in museums are illuminated with

A) infrared light.
B) ultraviolet light.
C) often either or both
D) none of these

back 236

B) ultraviolet light.

Topic: Fluorescence

front 237

The greater proportion of energy immediately converted to heat rather than light occurs in

A) a fluorescent lamp.
B) an incandescent lamp.
C) both the same

back 237

B) an incandescent lamp.

Topic: Fluorescence, Incandescence

front 238

Light from two closely spaced stars will not produce a steady interference pattern at the Earth's surface because of

A) incoherence.
B) the inherent instability of the atmosphere.
C) their different radial distances.
D) their non-point like natures.
E) Closely spaced stars do produce interference patterns.

back 238

A) incoherence.

Topic: Light Waves

front 239

A photographer wishes to use a safety light in the darkroom that will emit low-energy photons. The best visible color to use is

A) violet.
B) blue.
C) green.
D) actually any of these
E) none of these

back 239

E) none of these

Topic: Light Emission

front 240

Discrete spectral lines occur when excitation takes place in a

A) solid.
B) liquid.
C) gas.
D) superconductor.
E) all of these

back 240

C) gas.

Topic: Emission Spectra

front 241

Light frequency from an incandescent lamp depends on the

A) amount of electrical energy transformed.
B) rate of atomic and molecular vibrations.
C) voltage applied to the lamp.
D) electrical resistance of the lamp.
E) transparency of glass.

back 241

B) rate of atomic and molecular vibrations.

Topic: Incandescence

front 242

Isolated bells ring clear, while bells crammed in a box have a muffled ring. If the sound of isolated bells is analogous to light from a gas discharge tube, then sound from the box crammed with bells is analogous to light from

A) a laser.
B) a fluorescent lamp.
C) an incandescent lamp.
D) a phosphorescent source.
E) none of these

back 242

C) an incandescent lamp.

Topic: Incandescence

front 243

An atom that emits a certain frequency of light is

A) not likely to absorb that same frequency.
B) an absorber of the same frequency.

back 243

B) an absorber of the same frequency.

Topic: Light Emission

front 244

The dark lines in the sun's spectrum represent light that is

A) absorbed by the sun's atmosphere.
B) emitted by the sun.
C) not emitted by the sun.

back 244

A) absorbed by the sun's atmosphere.

Topic: Absorption Spectra

front 245

Spectral lines take the shape of vertical lines because

A) the light is vertically polarized.
B) they are simply images of a vertical slit.
C) the energy levels in the atom are parallel to one another.
D) all of these
E) none of these

back 245

B) they are simply images of a vertical slit.

Topic: Emission Spectra

front 246

Helium was first discovered in the

A) laboratory.
B) upper atmosphere.
C) sun.
D) island of Helios, in Greece.
E) by-products of nuclear fusion.

back 246

C) sun.

Topic: Absorption Spectra

front 247

Astronomers can tell whether a star is approaching or receding from Earth by

A) its temperature.
B) its change in temperature.
C) its absorption spectra.
D) the Doppler effect.
E) all of these

back 247

D) the Doppler effect.

Topic: Incandescence, Doppler Shift

front 248

Atoms can be excited by

A) thermal agitation.
B) electron impact.
C) photon impact.
D) all of these
E) none of these

back 248

D) all of these

Topic: Light Emission

front 249

Compared to the energy put into a laser, the energy of the laser beam is

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

back 249

B) less.

Topic: Lasers
In the process of fluorescence, the input is high-frequency light and the output is

A) higher-frequency light.
B) equally high-frequency light.
C) lower-frequency light.+
C) lower-frequency light

Topic: Fluorescence

front 250

In the process of fluorescence, part of the input energy immediately

A) becomes internal energy and the rest lower-frequency light.
B) cascades to excite other atoms in the material.
C) is emitted as higher-frequency light and the rest lower- frequency light.
D) excites electrons to metastable states.
E) none of these

back 250

A) becomes internal energy and the rest lower-frequency light.

Topic: Fluorescence

front 251

The white light emitted by a fluorescent lamp is provided by the

A) mercury vapor in the lamp.
B) phosphors on the inner surface of the lamp.
C) high temperature of the glowing gas.
D) filtering effect of the glass tubing.

back 251

B) phosphors on the inner surface of the lamp.

Topic: Fluorescence

front 252

The main visible difference between phosphorescent and fluorescent materials is

A) an afterglow.
B) a difference in brightness.
C) the greenish color of phosphorescence.

back 252

A) an afterglow.

Topic: Fluorescence, Phosphorescence

front 253

Light from a laser is

A) monochromatic.
B) in phase.
C) coherent.
D) all of these
E) none of these

back 253

D) all of these

Topic: Lasers

front 254

The efficiency of classroom lasers is typically

A) about one percent.
B) about ten percent.
C) about twenty percent.
D) appreciably more than twenty percent.

back 254

A) about one percent.

Topic: Lasers

front 255

The fact that the air you breathe doesn't give off much visible light indicates that most of the electrons of its atoms are

A) in the ground state.
B) excited to metastable states.
C) relatively cool.
D) electrically neutral.
E) relatively far apart.

back 255

A) in the ground state.

Topic: Light Emission

front 256

Green light emitted by excited mercury vapor corresponds to a particular energy transition in the mercury atom. A more energetic transition might emit

A) red light.
B) blue light.
C) either red or blue light.
D) white light.

back 256

B) blue light.

Topic: Light Emission

front 257

If the energy levels in the neon atom were not discrete, neon signs would glow

A) red.
B) white.
C) blue.

back 257

B) white.

Topic: Excitation

front 258

If light in a spectroscope were passed through a star-shaped opening instead of a thin slit, spectral lines would appear as

A) lines, but with poorer resolution.
B) stars.
C) blobs of no definite shape.

back 258

B) stars.

Topic: Emission Spectra

front 259

If light in a spectroscope passed through round holes instead of slits, spectral lines would appear
A) as thicker lines.

B) round.
C) dimmer.

back 259

B) round.

Topic: Emission Spectra

front 260

The fact that iron absorption lines occur in the solar spectrum directly indicates that there is iron in the solar

A) atmosphere.
B) surface.
C) interior.

back 260

A) atmosphere.

Topic: Absorption Spectra

front 261

A certain object emits infrared waves. If it were to emit light waves instead, its temperature would have to be

A) higher.
B) lower.
C) the same, temperature doesn't make any difference.

back 261

A) higher.

Topic: Light Emission

front 262

Which of the following continually emits electromagnetic radiation?

A) insects
B) radio antennas
C) red-hot coals
D) all of these
E) none of these

back 262

D) all of these

Topic: Light Emission

front 263

Sometimes a flashlight filament glows red instead of white. This indicates a lowness of

A) current in the filament.
B) battery strength.
C) filament temperature.
D) all of these
E) none of these

back 263

D) all of these

Topic: Incandescence

front 264

The radiation curve for a "red hot" object peaks in the

A) infrared region.
B) green region.
C) ultraviolet region.

back 264

A) infrared region.

Topic: Incandescence

front 265

The radiation curve for a "blue hot" object peaks in the

A) infrared region.
B) red region.
C) yellow region.
D) ultraviolet region.
E) none of these

back 265

D) ultraviolet region.

Topic: Incandescence

front 266

A paint pigment that absorbs red light and gives off blue light

A) is fluorescent.
B) is phosphorescent.
C) is used in lasers.
D) is polarized.
E) doesn't exist.

back 266

E) doesn't exist.

Topic: Light Emission

front 267

A paint pigment that absorbs blue light and gives off red light

A) is fluorescent.
B) is phosphorescent.
C) is used in lasers.
D) is fluorescent or phosphorescent.
E) doesn't exist.

back 267

D) is fluorescent or phosphorescent.

Topic: Fluorescence, Phosphorescence

front 268

The absorption of an infrared photon that excites an atom to emit a green photon

A) occurs in plants.
B) occurs in the process of phosphorescence.
C) violates the law of energy conservation.
D) all of these
E) none of these

back 268

C) violates the law of energy conservation.

Topic: Light Emission

front 269

The hottest star is the star that glows

A) red.
B) white.
C) blue.
D) cannot be determined by color alone

back 269

C) blue.

Topic: Incandescence

front 270

Comparing the light from a glowing tube of neon gas with light in the beam of a helium-neon laser, we find the greater number of spectral lines in light from the

A) neon gas tube.
B) laser beam.
C) both about the same

back 270

A) neon gas tube.

Topic: Excitation, Lasers

front 271

The red laser beam from a helium-neon laser corresponds to a spectral line of

A) helium.
B) neon.
C) both of these
D) neither of these

back 271

B) neon.

Topic: Lasers

front 272

For absorption spectra to exist

A) the light source must be a gas.
B) partially absorbent material must exist between the light source and spectroscope.
C) the spectroscope must be equipped with an absorption cell.
D) all of these
E) none of these

back 272

B) partially absorbent material must exist between the light source and spectroscope.

Topic: Absorption Spectra

front 273

Light from a phosphorescent source

A) takes longer to travel from the source to you.
B) normally has a shorter wavelength than the light that initially produced it.
C) is cooler than light from a fluorescent source.
D) all of these
E) none of these

back 273

E) none of these

Topic: Phosphorescence

front 274

Which light source is more energy-efficient?

A) a fluorescent lamp
B) an incandescent lamp
C) both about the same

back 274

A) a fluorescent lamp

Topic: Light Emission

front 275

The energy of a photon depends on its

A) speed.
B) frequency.
C) amplitude.
D) all of these
E) none of these

back 275

B) frequency.

Topic: Excitation

front 276

Some minerals glow when illuminated with ultraviolet light. This is because

A) ultraviolet photons kick atomic electrons in the mineral into higher energy states.
B) ultraviolet photons have such high energy.
C) of selective reflection.
D) of selective transmission.
E) none of these

back 276

A) ultraviolet photons kick atomic electrons in the mineral into higher energy states.

Topic: Fluorescence

front 277

Some light switches glow in the dark after the lights are turned off. This is because of

A) fluorescence.
B) resonance.
C) incandescence.
D) a time delay between excitation and de-excitation.
E) none of these

back 277

D) a time delay between excitation and de-excitation.

Topic: Phosphorescence

front 278

A watch dial that continues to glow after a week in the dark is almost certainly

A) fluorescent.
B) phosphorescent.
C) polarized.
D) radioactive.

back 278

D) radioactive

Topic: Phosphorescence

front 279

The Doppler effect from the back-and-forth motion of atoms in a glowing discharge tube tends to make the spectral lines slightly

A) thicker.
B) thinner.
C) more numerous.
D) none of these

back 279

A) thicker.

Topic: Light Emission

front 280

The spectral lines are more distinct when viewed in a mercury vapor lamp under

A) high pressure.
B) low pressure.
C) same for each

back 280

B) low pressure.

Topic: Light Emission

front 281

Under very high pressure, the spectrum of a mercury vapor lamp begins to look like that from

A) an incandescent source.
B) a laser.
C) an ultraviolet source.
D) a gas other than mercury.
E) a monochromatic source.

back 281

A) an incandescent source.

Topic: Light Emission

front 282

Materials can be heated until "red hot." If some material is heated until it is "green hot," then

A) it would liquefy immediately.
B) it would be hotter than "white hot."
C) its molecules would be vibrating at nearly identical rates.
D) it would be a strong absorber of red light.
E) energy conservation would be violated.

back 282

C) its molecules would be vibrating at nearly identical rates.

Topic: Light Emission

front 283

If the radiation curve for an incandescent object peaks in the green region, the object would appear

A) red.
B) yellow.
C) green.
D) blue.
E) white.

back 283

E) white

Topic: Incandescence

front 284

No laser can emit more energy than is put into it. Can a laser emit more power than is put into it?

A) No.
B) Yes, although not continuously.
C) It is too early in our technological development to answer this question with a reasonable degree of certainty.

back 284

B) Yes, although not continuously.

Topic: Lasers

front 285

As a solid is gradually heated, the first color to glow is

A) red.
B) yellow.
C) white.
D) blue.

back 285

A) red.

Topic: Light Quanta