Reference no: EM131032500

PART 1:

1. What does a changing magnetic field induce?

2. What does a changing electric field induce?

3. What produces an electromagnetic wave?

4. What is the color of visible light of the lowest frequencies? Of the highest frequencies?

5. What is the fate of the energy in ultraviolet light that is incident upon glass?

6. Why do opaque materials become warmer when light shines on them?

7. When are objects on the periphery of your vision most noticeable?

8. In 1676, the Danish astronomer Ole Roemer had one of the "aha" moments in science. He concluded form accumulated observations of eclipses of Jupiter's moon at different time of the year that light must travel at finite speed and needed 1300 s to cross the diameter of Earth's orbit around the Sun. Using 300,000,000 km for the diameter of Earth's orbit, calculate the speed of light based on Roemer's 1300-s estimate. How does it differ from a modern value for the speed of light?

9. The Sun is 1.5 1011 m from Earth. How long does it take the Sun's light to reach Earth? How long does it take light to cross the diameter of Earth's orbit? Compare the time with the time measured by Roemer in the 17th century.

10. The nearest star beyond the Sun is Alpha Centauri, 4.2 x 1016 m away. If we were to receive a radio message from this star today, show that is would have been sent 4.4 years ago.

11. You can get a sunburn on a cloudy day, but you can't get a sunburn even on a sunny day if you are behind glass. Explain.

12. Suppose that sunlight falls both on a pair of reading glasses and on a pair of dark sunglasses . Which pair of glasses would you expect to become warmer? Defend you answer.

13. Why don't we see color at the periphery of our vision?

14. Which has the higher frequency: red light or blue light?

15. What occurs when the outer electrons that buzz about the atomic nucleus encounter electromagnetic waves?

16. What happens to light when it falls on a material that has a natural frequency equal to the frequency of the light?

17. What happens to light when it falls on a material that has a natural frequency above or below the frequency of the light?

18. Why are red, green and blue called the additive primary colors?

19. What are the subtractive primary colors?

20. Why does the sky normally appear blue?

21. Why does the Sun look reddish at sunrise and sunset by not at noon?

22. What part of the electromagnetic spectrum is most absorbed by water?

23. What part of the visible electromagnetic spectrum is most absorbed by water?

24. Why does water appear cyan?

25. Why don't color scientists list black and white as colors?

26. What is Fermat's principle of least time?

27. Cite the law of reflection.

28. Relative to the distance of an object in front of a plane mirror, how far behind the mirror is the image?

29. Why is a secondary rainbow dimmer than a primary bow?

30. Distinguish between virtual image and a real image.

31. Suppose you walk toward a mirror at 2 m/s. How fast do you and your image approach each other? (The answer is not 2 m/s.)

32. Car mirrors are uncoated on the from surface and silvered on the back surface. When the mirror is properly adjusted, light from behind reflects from the silvered surface into the driver's eyes. Good. But this not so good at nighttime with the glare of headlights behind. This problem is solved by the wedge shape of the mirror (see the sketch). When the mirror is tilted slightly upward t the "nighttime" position, glare is directed upward toward the ceiling , away from the driver's eyes. Yet the driver can still see cares behind in the mirror. Explain.

33. A person in a dark room looking through a window can clearly see a person outside in the daylight, whereas the person outside cannot see the person inside. Explain.

34. What is the advantage of having matte (nonglossy) pages in this book rather than pages with a glossier surface?

35. What must be the minimum length of a plane mirror in order for you to see a full image of yourself?

36. According to Huygens, how does every point on a wave front behave?

37. Is diffraction more pronounced through a small opening or through a large opening?

38. For an opening of a given size, is diffraction more pronounced for a longer wavelength or for a shorter wavelength?

39. Which more easily diffracts around buildings: AM or FR radio waves? Why?

40. Is interference restricted to only some types of waves, or does it occur for all types of waves?

41. What aspect of light did Thomas Young demonstrate in his famous light experiment?

42. Why will light pass through a pair of Polaroids when the axes are aligned but when the axes are at right angles to each other?

43. When the reflected path from one surface of a thin film is one-half wavelength from the different in length from the reflected path from the other surface and not phase change occurs, will the result be destructive interference or constructive interference?

44. The colors of peacocks and hummingbirds are the result not of pigments but of ridges in the surface layers of their feathers. By what physical principle do these ridges produce color?

45. If you notice the interference patterns of a thin film of oil or gasoline on water, you'll see that the colors form complete rings. How are these rings similar to the lines of equal elevation on a contour map?

46. What does it mean to say an energy state is discrete?

47. Which has more potential energy relative to the nucleus: electrons in the inner electron shells or electrons in the outer electron shells?

48. How does the difference in energy between energy levels relate to the energy of the photon that is emitted by a transition between those levels?

49. Which has the higher frequency: red or blue light? Which has greater energy per photon: red or blue light?

50. Can a neon atom in a glass tube be excited more than once? Explain.

51. How does an absorption spectrum differ in appearance from an emission spectrum?

52. Distinguish between monochromatic light and sunlight.

53. Distinguish between coherent light and sunlight.

54. In what specific way does light from distant stars and galaxies tell astronomers that atoms throughout the universe have the same properties as those on Earth?

55. When ultraviolet light falls on certain dyes, visible light is emitted. Why doesn't this happen when infrared light falls on these dyes?

56. A friend speculates that scientists in a certain country have developed a laser that produces far more energy than is put into it and asks for your response. What is your response?

57. Going back to Chapter 16, since all bodies radiate energy, why don't all bodies become cooler?

58. Which theory of light, the wave theory or the particle theory, did the findings of Young, Maxwell, and Hertz support?

59. Which has the lower energy quanta: red light or blue light? Radio waves or X-rays?

60. Why won't a very bright beam of red light impart more energy to an ejected electron than a feeble beam of violet light?

61. When does light behave as a wave? When does it behave as a particle?

62. What evidence can you cite for the wave nature of particles?

63. What does it mean to say that something is quantized?

64. The frequency of violet light is about twice that of red li does the energy of a violet photo compare with the energy of a red photon?

65. We speak of photons of red light and photons of green light. Can we speak of photons of white light?

66. In the photoelectric effect, does brightness or frequency determine the kinetid energy of the ejected electrons?

67. Explain how the photoelectric effect is used to open automatic doors when some approaches.

68. Why do most alpha particles fired through a piece of gold foil emerge almost undeflected?

69. What did Rutherford discover about the atomic nucleus?

70. How does treating the electron as a wave rather than as a particle solve the riddle of why electron orbits are discrete?

71. In what way did Rutherford's gold-foil scattering experiment show that the atomic nucleus is both small and very massive?

72. How does Rutherford's model of the atom account for the back-scattering of alpha particles directed at the gold foil?

73. When an electron makes a transition from its first quantum level to ground level, the energy difference is carried by the emitted photon. In comparison, how much energy is needed to return an electron at ground level to the first quantum level?

74. In terms of wavelength, what is the smallest orbit that an electron can have about the atomic nucleus?

75. Why doesn't a stable electron orbit with a circumference of 2.5 de Broglie wavelengths exist in any atom?