physics chapter 28

1) Light is reflected when
A) electron clouds of atoms are energized.
B) atomic nuclei are made to vibrate.
C) incident light is returned into the medium from which it came.
D) electromagnetic waves emanate from matter.

c

2) When sunlight illuminates a page from your Conceptual Physics book it
A) reflects most of it.
B) absorbs at the text lettering.
C) both of these
D) neither of these

c

3) Light travels from one place to another along a path of least
A) distance.
B) time.
C) effort.
D) expense.
E) complication.

b

6) According to the law of reflection, 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.

a

7) Object and image for a plane mirror occur
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

b

8) 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 the above

c

10) 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.

b

11) Your image in a plane mirror is
A) virtual.
B) real.
C) both of these
D) neither of these

a

12) A rough surface for infrared waves may be polished for
A) radio waves.
B) light waves.
C) both of these
D) neither of these

a

13) When light reflects from a surface, there is a change in its
A) frequency.
B) wavelength.
C) speed.
D) all of the above
E) none of the above

e

14) A yellow candle flame reflects from opposite surfaces of a piece of red glass.
A) both images are yellow
B) one image is yellow and the other red
C) both images are red
D) both images are reddish yellow

b

15) You photograph the image of your little sister, who stands 2 meters in front of a plane mirror. Holding the camera beside her head, the distance to her image is
A) 1 meter.
B) 2 meters.
C) 3 meters.
D) 4 meters.
E) none of the above

d

16) 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 the above

c

17) 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

a

18) To see his full height, Blinky Bill who 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 distance from the mirror.

b

19) If you look at yourself in a pocket mirror, then hold the mirror farther away, you see
A) more of yourself.
B) less of yourself.
C) the same amount of yourself.

c

20) 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.

c

21) It is difficult to see the roadway when driving on a rainy night mainly because
A) light scatters from raindrops and reduces the amount of light reaching your eyes.
B) of additional 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 the above

d

22) 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 as with churning waves

b

23) Standing at the shore of a still lake, the reflected view of scenery on the other 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 the above

c

24) 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

b

25) 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%

c

26) 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%

b

27) Refraction occurs when light passing from one medium to another
A) changes frequency.
B) changes speed.
C) loses energy.
D) reflects inward.

b

28) Refraction results from differences in light’s
A) frequency.
B) incident angles.
C) speed.
D) all of the above
E) none of the above

c

29) Light refracts when traveling from air into glass because of a change in light’s
A) intensity.
B) frequency.
C) speed.
D) all of the above
E) none of the above

c

30) Light travels fastest in
A) warm air.
B) cool air.
C) a vacuum.

c

31) When a light ray in air enters water at 15° from the normal, it
A) always bends toward the normal.
B) always bends away from the normal.
C) sometimes bends towards or away from the normal.
D) does not bend.

a

32) When a light ray passes at a non-90° angle from water into air, it
A) bends toward the normal.
B) bends away from the normal.
C) travels much slower.

b

33) When light passes through common windowpane, 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.

c

34) A mirage is a result of atmospheric
A) reflection.
B) refraction.
C) scattering.
D) dispersion.
E) aberrations.

b

35) The twinkling of the stars is a result of atmospheric
A) reflection.
B) refraction.
C) scattering.
D) dispersion.
E) aberrations.

b

36) 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 of these

b

37) The average speed of light is greatest in
A) red glass.
B) orange glass.
C) green glass.
D) blue glass.
E) same in all of these

a

38) In which material does light travel fastest?
A) glass
B) water
C) plastic
D) air
E) same for all

d

39) Atmospheric refraction makes the daylight hours a bit
A) longer.
B) shorter.
C) longer in summer but shorter in winter.

a

40) When a pulse of white light is incident on a glass prism, the first color to emerge is
A) red.
B) orange.
C) green.
D) violet.

a

41) A fish above the surface of water will see better in air if it has goggles that are
A) tinted blue.
B) hemispherical.
C) filled with water.
D) extremely shiny.
E) none of the above

c

42) Stars twinkle when seen from Earth. When seen by an astronaut on the Moon, stars
A) twinkle more.
B) twinkle less.
C) don’t twinkle.

c

44) If the speed of light in a sphere is 2 × 108 m/s, its index of refraction is
A) 0.50.
B) 0.67.
C) 1.0.
D) 1.5.
E) 2.0.

d

45) Stephanie dips a glass rod into vegetable oil. The submerged part of the rod can’t be seen because
A) refraction is unbent before light gets to your eye.
B) both the oil and glass have the same index of refraction.
C) of internal reflection.
D) light has different speeds in the oil and glass.

b

46) When spearing a fish with a regular spear, to compensate for refraction, throw your spear
A) directly at the sighted fish.
B) above the sighted fish.
C) below the sighted fish.

c

47) To "spear" a red fish with a red laser beam and compensate for refraction, aim your laser
A) directly at the sighted fish.
B) above the sighted fish.
C) below the sighted fish.

a

49) To send a beam laser-light beam to a space station just 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.

c

50) The index of refraction for crown glass, common in eyeglasses, is 1.52. The index of refraction of a particular plastic lens is 1.76. Light bends more in the
A) crown glass.
B) plastic lens.
C) same speed in each.
D) need more information

b

56) 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.

e

57) Light of different colors in a vacuum travel at
A) different speeds.
B) the same speed.
C) the same speed in both a vacuum and all materials.

b

58) Light of different colors in a glass prism travel at
A) different speeds.
B) the same speed.
C) the same speed in prisms and all materials.

a

59) Which are consequences of different speeds of light in different media?
A) mirages
B) rainbows
C) brilliant colors of diamonds
D) all of the above
E) none of the above

d

61) As monochromatic light passes from air to glass and back to air, changes occur in its
A) wavelength.
B) speed.
C) both of these
D) neither of these

c

62) A mirage occurs when light travels faster
A) near the ground than higher up.
B) in less dense air than more dense air higher up.
C) both of these
D) neither of these

c

63) A mirage occurs for road surfaces that are most often
A) hot.
B) cold.
C) wet.
D) hard.
E) snowy.

a

64) When sunlight from air enters water, light that refracts most is
A) red.
B) orange.
C) green.
D) violet.
E) all refract the same amount

d

65) Rainbows exist because light is
A) reflected.
B) refracted.
C) both of these
D) neither of these

c

66) A single raindrop illuminated by sunshine disperses
A) a single color.
B) mainly light of mid-frequency colors.
C) all the colors of the rainbow.

c

67) 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) rain drops are not perfectly round.
E) rainbows are actually arched shaped.

a

68) When a rainbow is seen as a complete circle from an airplane, the airplane’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.

a

71) If you view a rainbow out your window while riding in a train, you’ll see that
A) the rainbow can only be seen while you’re moving slowly or at rest.
B) the rainbow moves along with you.
C) you soon pass by it, leaving it where you first saw it.

b

72) The critical angle for a transparent material is the angle at and beyond which all light within the material at its upper surface is
A) refracted.
B) reflected.
C) absorbed.
D) dispersed.
E) diffused.

b

75) When a light beam emerges from water into air, light speed
A) increases.
B) decreases.
C) remains the same.

a

76) The critical angle is least in
A) glass.
B) water.
C) diamond.
D) vacuum.

c

77) A diver shines light upward to the surface of a smooth pond at 20° to the normal. Most light passes into the air above while the part that reflects back into the water makes an angle to the normal of
A) less than 20°.
B) 20°.
C) more than 20°.
D) all refracts, none reflects.
Answer: B

b

79) At night an underwater scuba diver aims a flashlight beam toward the surface at 15° to the normal. Upon emerging into the air, the beam angle will be
A) less than 15°.
B) 15°.
C) more than 15°.
D) impossible to predict.

c

80) The refraction of light in a diamond is greater for
A) long-wavelength light.
B) short-wavelength light.
C) both refract the same

b

81) 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

b

82) Optical fibers are commonly used by
A) surgeons.
B) mechanics.
C) engineers.
D) aviators.
E) all of the above

e

83) The type of lens that spreads parallel light is a
A) converging lens.
B) diverging lens.
C) combination of converging-diverging lens.

b

84) The type of lens that brings parallel light rays together is a
A) converging lens.
B) diverging lens.
C) combination of converging-diverging lens.

a

85) Which of the following can be projected onto a viewing screen?
A) a real image
B) a virtual image
C) both of these
D) neither of these

a

86) A "burning glass" used to concentrate sunlight in a tiny spot is a
A) converging lens.
B) diverging lens.
C) either of these
D) neither of these

a

87) Your vision is sharpest when your pupil is
A) dilated.
B) constricted.
C) same either way

b

88) The image in a pinhole camera is
A) always inverted.
B) sometimes inverted.
C) always right-side up.

a

89) When the tiny hole in a pinhole camera is made larger, the image is
A) brighter but less clear.
B) clearer.
C) right-side up.
D) none of the above

a

92) In a converging lens, objects infinitely far away are focused
A) in front of the focal point.
B) at the focal point.
C) beyond the focal point.

b

93) 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.

b

97) Light travels slower in a lens having a
A) high index of refraction.
B) low index of refraction.
C) same in each

a

98) When taking a photo of a nearby flower, your camera lens should be set
A) closer than one focal length from the photosensitive surface.
B) farther than one focal length from the photosensitive surface.
C) to one focal length from the photosensitive surface.

b

99) Chromatic aberration is a consequence of different colors in a lens having different
A) aberrations.
B) frequencies.
C) energies.
D) critical angles.
E) speeds.

e

100) Chromatic aberration is absent in
A) converging lenses
B) diverging lenses.
C) front surface plane mirrors.

c

102) If you cover half a camera lens with opaque tape, the images produced will be
A) cut in half.
B) only dimmer.
C) both of these
D) neither of these

b