Q&A Hero

Q: An ideal Polaroid will transmit 50% of incident sunlight. How much light will be transmitted by two ideal Polaroids oriented with their axes parallel to each other? A) 0% B) 50% C) 100% D) between 0% and 50% E) between 50% and 100%

Q: A pair of crossed Polaroids will transmit light A) of sufficiently long wavelengths. B) that itself is polarized. C) if a third Polaroid at about 45 degrees is inserted between the two.

Q: For a pair of Polaroids with axes at 45 degrees to each other A) light will not pass. B) light that passes is dimmer than for a parallel orientation. C) another Polaroid is necessary for any light to pass.

Q: Light will pass through a pair of Polaroids when their axes are A) 45 degrees to each other. B) parallel. C) either of these D) neither of these

Q: Light will NOT pass through a pair of Polaroids when their axes are A) 45 degrees to each other. B) parallel. C) perpendicular. D) all of the above E) none of the above

Q: A painting looks less flat when viewed with A) one eye. B) both eyes. C) Polaroid glasses.

Q: The polarization axes of glasses for 3-D viewing are A) vertical. B) horizontal. C) at right angles to each other.

Q: Parallax is evident when you view objects A) with one eye. B) with both eyes. C) with one or both eyes. D) in a completely dark room.

Q: Three-dimensional viewing normally involves A) parallax. B) two-eye vision. C) an ability to see 'around' things. D) all of the above E) none of the above

Q: Polaroid sunglasses reduce much glare by polarization axes that are A) vertical. B) horizontal. C) at right angles to each other.

Q: The glare seen from water is largely A) horizontally polarized. B) vertically polarized. C) unpolarized.

Q: Light emitted by the Sun is A) polarized. B) nonpolarized. C) sometimes polarized.

Q: Light travels through non-cubic transparent crystals 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 the above

Q: The vibrational direction of an 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.

Q: Some double-pane airplane windows darken when the inner pane is rotated. The panes are A) thin films. B) Polaroid filters. C) optical fibers.

Q: An inventor proposes to equip an office with a polarized source of background music and polarizing earplugs for non-listeners. His idea is A) a good one that provides personal choice. B) too expensive. C) bothersome. D) nonsense because sound cannot be polarized.

Q: Which of the following is a property of light waves and NOT of sound waves? A) frequency B) wavelength C) amplitude D) polarization E) none of the above

Q: Polarization is a property of A) transverse waves. B) longitudinal waves. C) both of these D) neither of these

Q: 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) are out of phase with one another. D) are too displaced to interfere.

Q: A thin film appears magenta when illuminated with white light. The color being cancelled by destructive interference is A) red. B) green. C) white. D) blue. E) none of the above

Q: A thin film appears cyan when illuminated with white light. The color being cancelled by destructive interference is A) red. B) green. C) white. D) blue. E) none of the above

Q: A thin film appears yellow when illuminated with white light. The color being cancelled by destructive interference is A) red. B) green. C) white. D) blue. E) none of the above

Q: The production of interference colors requires A) a reflecting surface. B) at least two reflecting surfaces. C) a medium with a relatively low index of refraction. D) none of the above

Q: Consider the interference colors in a film of gasoline on a wet street. The water provides 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 the above

Q: When you view color in a soap film with sunlight in back of you, a friend on the other side of the soap film likely sees A) the same color. B) a different color. C) only your head.

Q: 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 of these

Q: Interference colors in a soap bubble is evidence that the soap film A) has two reflecting surfaces. B) is thin. C) both of these D) neither of these

Q: Colors seen when gasoline forms a thin film on water illustrate A) refraction. B) reflection. C) dispersion. D) polarization. E) interference.

Q: Iridescent colors in the pearly luster of an abalone shell are due to A) refraction. B) diffraction. C) dispersion. D) polarization. E) interference.

Q: In the double-slit experiment, fringes are more widely spaced when illumination is with monochromatic A) low-frequency light. B) high-frequency light. C) polarized light. D) none of the above

Q: Successive bright fringes in an interference pattern result from A) equal-length distances from the slits. B) distance from the slits successively increasing one wavelength at a time. C) destructive interference. D) none of the above

Q: Light from two closely-spaced stars cannot produce a steady interference pattern due to A) incoherence. B) the inherent instability of the atmosphere. C) their different radial distances. D) their non-point like natures. E) closely spaced stars not producing interference patterns.

Q: Newton's rings will be closer together if illuminated with A) red light. B) blue light. C) white light. D) none of the above

Q: Newton's rings illustrate A) refraction. B) reflection. C) dispersion. D) polarization. E) interference.

Q: When waves from a pair of closely-spaced slits arrive out of phase A) a bright fringe is produced. B) a dark fringe is produced. C) both bright and dark fringes are produced. D) none of the above

Q: When waves from a pair of closely-spaced slits arrive in phase A) a bright fringe is produced. B) a dark fringe is produced. C) both bright and dark fringes are produced. D) none of the above

Q: Thomas Young's two-source interference patterns demonstrate the A) particle nature of light. B) wave nature of light. C) both of these D) neither of these

Q: Monochromatic light is light of a single A) wavelength. B) frequency. C) color. D) all of the above E) none of the above

Q: Interference is a property of A) light waves. B) sound waves. C) water waves. D) all of the above E) none of the above

Q: The superposition of identical waves affects A) amplitude. B) wavelength. C) speed. D) all of the above E) none of the above

Q: Superposition of waves can produce A) reinforcement. B) cancellation. C) partial cancellation. D) all the above

Q: Diffraction is least when illumination is with A) red light. B) blue light. C) an electron beam D) none of the above

Q: The device that spreads light into its component colors in a spectroscope is a A) prism. B) diffraction grating. C) either of these D) neither of these

Q: A razor blade nicely shows diffraction fringes when illuminated with A) ultraviolet light. B) monochromatic light. C) sunlight. D) all of the above E) none of the above

Q: For radio reception in city buildings, diffraction is A) helpful. B) a hindrance. C) not a factor.

Q: For viewing tiny objects in a microscope, diffraction is A) helpful. B) a hindrance. C) not a factor.

Q: A dolphin perceives greater detail by emitting sounds of A) lower frequency. B) higher frequency. C) greater intensity. D) greater speed. E) none of the above

Q: Radio waves that diffract more around small buildings are A) AM. B) FM. C) both diffract equally

Q: Waves diffract the most when their wavelength is A) short. B) long. C) both of these D) neither of these

Q: What can exist in the same place at the same time? A) two large boulders B) two tiny boulders C) two waves D) all of the above E) none of the above

Q: Diffraction is evident when a wave passes A) through a small opening. B) the edge of an object. C) both of these D) neither of these

Q: Diffraction from foghorns is best if the waves being diffracted are A) long. B) short. C) either of these D) neither of these

Q: Diffraction is most closely related to A) refraction. B) reflection. C) interference. D) polarization. E) dispersion.

Q: Plane waves incident upon a barrier that pass through a small opening A) continue as plane waves. B) fan out. C) converge. D) become polarized. E) all of the above

Q: The fanning out of waves upon passing through an opening is more pronounced through A) small openings. B) large openings. C) same for each D) none of the above

Q: Huygens' principle applies mainly to A) refraction of waves in a medium. B) reflection of waves. C) both of these D) neither of these

Q: Secondary wavelets spread from a wave with A) reduced speed. B) an unchanging speed. C) an increased speed. D) none of the above

Q: 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 the above E) none of the above

Q: 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

Q: 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

Q: If a fish looks upward at 45o to a pond's water's surface, it will see A) the pond's bottom. B) the sky and possibly some tall surroundings. C) only the water's surface. D) none of the above

Q: 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

Q: 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.

Q: 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.

Q: 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.

Q: The Moon's redness during a lunar eclipse is due to A) light of lower frequencies reflected from the Moon. B) excess infrared radiation. C) an optical illusion. D) refracted light from Earth's sunrises and sunsets. E) none of the above

Q: When a colored light in air shines on water and is refracted, its frequency A) decreases. B) remains unchanged. C) increases.

Q: When a colored light in air shines on water and is refracted, its wavelength A) shortens. B) remains unchanged. C) lengthens.

Q: When light is refracted, there is a change in its A) frequency. B) wavelength. C) both of these D) neither of these

Q: A person who sees more clearly under water without eyeglasses or a facemask is A) nearsighted. B) farsighted. C) neither of these

Q: 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

Q: 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.

Q: To "spear" a blue 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.

Q: 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.

Q: 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.

Q: 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.

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

Q: 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) neither of these

Q: 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.

Q: 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