Chapter 28: Reflection And Refraction

87 Questions
Chapter 28: Reflection And Refraction
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Questions and Answers
  • 1. 
    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.

  • 2. 
    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.

  • 3. 
    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.

  • 4. 
    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

  • 5. 
    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.

  • 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.

  • 7. 
    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

  • 8. 
    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

  • 9. 
    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

  • 10. 
    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.

  • 11. 
    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

  • 12. 
    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

  • 13. 
    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.

  • 14. 
    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.

  • 15. 
    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.

  • 16. 
    • 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

  • 17. 
    • 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

  • 18. 
    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

  • 19. 
    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

  • 20. 
    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.

  • 21. 
    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%

  • 22. 
    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.

  • 23. 
    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.

  • 24. 
    • 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.

  • 25. 
    Light travels fastest in
    • A. 

      Warm air.

    • B. 

      Cool air.

    • C. 

      A vacuum.

  • 26. 
    Atmospheric refraction makes the daylight hours a bit
    • A. 

      Longer.

    • B. 

      Shorter.

    • C. 

      Longer in summer but shorter in winter.

  • 27. 
    A mirage is a result of atmospheric
    • A. 

      Reflection.

    • B. 

      Refraction.

    • C. 

      Scattering.

    • D. 

      Dispersion.

    • E. 

      Aberrations.

  • 28. 
    The twinkling of the stars is a result of atmospheric
    • A. 

      Reflection.

    • B. 

      Refraction.

    • C. 

      Scattering.

    • D. 

      Dispersion.

    • E. 

      Aberrations.

  • 29. 
    Refraction results from differences in light's
    • A. 

      Frequency.

    • B. 

      Incident angles.

    • C. 

      Speed.

    • D. 

      All of these

    • E. 

      None of these

  • 30. 
    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.

  • 31. 
    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.

  • 32. 
    When a light beam emerges from water into air, the average light speed
    • A. 

      Increases.

    • B. 

      Decreases.

    • C. 

      Remains the same.

  • 33. 
    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.

  • 34. 
    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

  • 35. 
    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

  • 36. 
    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.

  • 37. 
    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.

  • 38. 
    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.

  • 39. 
    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.

  • 40. 
    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.

  • 41. 
    The critical angle is least in which of the following?
    • A. 

      Glass

    • B. 

      Water

    • C. 

      Diamond

    • D. 

      Vacuum

  • 42. 
    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.

  • 43. 
    Optical fibers are now used by
    • A. 

      Surgeons.

    • B. 

      Mechanics.

    • C. 

      Engineers.

    • D. 

      All of these

  • 44. 
    Your image in a plane mirror is
    • A. 

      Virtual.

    • B. 

      Real.

    • C. 

      Both of these

    • D. 

      Neither of these

  • 45. 
    The type of lens that spreads parallel light is a
    • A. 

      Converging lens.

    • B. 

      Diverging lens.

    • C. 

      Combination converging-diverging lens.

  • 46. 
    Which of the following can be projected onto a viewing screen?
    • A. 

      A real image

    • B. 

      A virtual image

    • C. 

      Both

    • D. 

      Neither

  • 47. 
    A "burning glass" used to concentrate sunlight in a tiny spot is a
    • A. 

      Converging lens.

    • B. 

      Diverging lens.

    • C. 

      Either

    • D. 

      neither

  • 48. 
    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.

  • 49. 
    The image in a pinhole camera is
    • A. 

      Always inverted.

    • B. 

      Sometimes inverted.

    • C. 

      Always right-side up

  • 50. 
    When the pinhole in a pinhole camera is made larger, the image is
    • A. 

      Brighter.

    • B. 

      Clearer.

    • C. 

      Both

    • D. 

      Neither

  • 51. 
    Your vision is sharpest when your pupil is
    • A. 

      Dilated.

    • B. 

      Constricted.

    • C. 

      Same either way.

  • 52. 
    Chromatic aberration is absent in
    • A. 

      Converging lenses

    • B. 

      Diverging lenses.

    • C. 

      Front surface plane mirrors.

  • 53. 
    Chromatic aberration is a consequence of different colors in a lens having different
    • A. 

      Aberrations.

    • B. 

      Frequencies.

    • C. 

      Energies.

    • D. 

      Critical angles.

    • E. 

      Speeds.

  • 54. 
    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.

  • 55. 
    Fermat's principle of least time applies to
    • A. 

      Reflection.

    • B. 

      Refraction.

    • C. 

      Both of these

    • D. 

      Neither of these

  • 56. 
    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

  • 57. 
    A beam of light travels fastest in
    • A. 

      Glass.

    • B. 

      Water.

    • C. 

      Plastic.

    • D. 

      Air.

    • E. 

      Is the same in each of these

  • 58. 
    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.

  • 59. 
    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

  • 60. 
    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

  • 61. 
    Stars twinkle when seen from the Earth. When seen from the moon, stars
    • A. 

      Twinkle more.

    • B. 

      Twinkle less.

    • C. 

      Don't twinkle.

  • 62. 
    Atmospheric refraction tends to make daytimes
    • A. 

      Longer.

    • B. 

      Shorter.

    • C. 

      No change in day length

  • 63. 
    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

  • 64. 
    Rainbows exist because light is
    • A. 

      Reflected.

    • B. 

      Refracted.

    • C. 

      Both of these

    • D. 

      Neither of these

  • 65. 
    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.

  • 66. 
    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.

  • 67. 
    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.

  • 68. 
    The refraction of light in a diamond is greater for
    • A. 

      Long-wavelength light.

    • B. 

      Short-wavelength light.

    • C. 

      Both refract the same.

  • 69. 
    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

  • 70. 
    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

  • 71. 
    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.

  • 72. 
    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.

  • 73. 
    • A. 

      Yes.

    • B. 

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

    • C. 

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

  • 74. 
    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.

  • 75. 
    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.

  • 76. 
    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.

  • 77. 
    A person who sees more clearly under water without eyeglasses or a face mask is
    • A. 

      Nearsighted.

    • B. 

      Farsighted.

    • C. 

      Neither

  • 78. 
    A mirage occurs for surfaces that are
    • A. 

      Horizontal.

    • B. 

      Vertical.

    • C. 

      Both of these

  • 79. 
    A mirage occurs for road surfaces that are
    • A. 

      Warm.

    • B. 

      Cold.

    • C. 

      Wet.

    • D. 

      Hard.

    • E. 

      Snowy.

  • 80. 
    When light is refracted, there is a change in its
    • A. 

      Frequency.

    • B. 

      Wavelength.

    • C. 

      Both of these

    • D. 

      Neither of these

  • 81. 
    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

  • 82. 
    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.

  • 83. 
    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

  • 84. 
    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.

  • 85. 
    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%

  • 86. 
    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.

  • 87. 
    If the speed of light in a medium is 2 × 10^8 m/s, the medium's index of refraction is
    • A. 

      0.50.

    • B. 

      0.67.

    • C. 

      1.0.

    • D. 

      1.5.

    • E. 

      2.0.