Deck 14: Properties of Light

Question 1

The incident light ray, the reflected light ray, and the normal between them

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

Answer 1

lie in the same plane.

Question 2

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

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

Answer 2

red.

Question 3

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

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

Answer 3

Both images are yellow-white.

Question 4

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.

Question 5

Rainbows exist because light is

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

Question 6

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.

Question 7

Objects infinitely far away are focused by a converging lens

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

Question 8

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

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

Question 9

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

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

Question 10

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

Question 11

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

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

Question 12

Magnification from a lens would be greater if light

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

Question 13

Reflected light from the moon in a lake often appears as a vertical column when the water is

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

Question 14

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

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

Question 15

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

Question 16

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

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

Question 17

Atmospheric refraction tends to make daytimes

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

Question 18

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

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

Question 19

In optical fibers of uniform density, light actually

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

Question 20

Light is emitted when

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

Question 21

Refraction results from differences in light's

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

Question 22

Light refracts when traveling from air into glass because light

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

Question 23

Refraction causes the bottom of a swimming pool to appear

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

Question 24

A primary rainbow is brighter than a secondary rainbow because

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

Question 25

Optical fibers are now used by

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

Question 26

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

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

Question 27

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

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

Question 28

The refraction of light in a diamond is greater for

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

Question 29

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

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

Question 30

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

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

Question 31

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

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

Question 32

A mirage occurs for road surfaces that are

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

Question 33

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

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

Question 34

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

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

Question 35

Light travels fastest in

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

Question 36

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

Question 37

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) along your line of sight.
C) below your line of sight.

Question 38

A mirage occurs for surfaces that are

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

Question 39

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

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

Question 40

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

Question 41

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

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

Question 42

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

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

Question 43

The image in a pinhole camera is

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

Question 44

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

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

Question 45

As you face a plane mirror on the east wall of your room, you raise your north hand. Your image raises

A) its north hand.
B) its south hand.
C) its left hand.
D) neither hand.
E) both hands.

Question 46

Polarization is a property of

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

Question 47

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

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

Question 48

The first ones to use optical fibers were

A) polar bears.
B) physicists.
C) engineers.
D) surgeons.
E) mechanics.

Question 49

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

A) nearsighted.
B) farsighted.
C) neither

Question 50

The reason diamonds display many colors is that

A) different colors of light undergo different changes of speed when exiting a diamond.
B) a diamond reflects much more light than it absorbs.
C) diamonds are forever.
D) diamonds are extremely hard.
E) none of these

Question 51

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

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

Question 52

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

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

Question 53

A beam of light travels fastest in

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

Question 54

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

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

Question 55

The average speed of light is greatest in

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

Question 56

The polarization axes of glasses for 3-D viewing are

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

Question 57

At night an underwater scuba diver aims his flashlight beam toward the surface at an angle of 45 degrees with the normal. Upon emerging, the beam angle will be

A) 45 degrees.
B) less than 45 degrees.
C) more than 45 degrees.
D) impossible to predict.

Question 58

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

Question 59

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

Question 60

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

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

Question 61

A mirage is a result of atmospheric

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

Question 62

If you view exact duplicates of slides in the left and right positions of a stereo projector, you can see

A) depth.
B) no depth.

Question 63

To see his full height, a boy that is 1 meter tall needs a mirror that is at least

A) 1 m tall.
B) 0.50 m tall.
C) 0.33 m tall.
D) 0.75 m tall.
E) depends on how far the mirror is from the boy

Question 64

When you view a distant rainbow, you view from each single water drop that 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.

Question 65

Rainbows are not usually seen as complete circles because

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

Question 66

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

Question 67

The type of lens that spreads parallel light is a

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

Question 68

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

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

Question 69

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

Question 70

The law of reflection holds for

A) curved mirrors.
B) plane mirrors.
C) both of these
D) neither of these

Question 71

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

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

Question 72

Your image in a plane mirror is

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

Question 73

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

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

Question 74

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

Question 75

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

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

Question 76

The secondary rainbow is dimmer than the primary rainbow because

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

Question 77

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

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

Question 78

The moon's redness during a lunar eclipse results from

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

Question 79

Your vision is sharpest when your pupil is

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

Question 80

The polarization axes of ordinary sunglasses are

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