Chapter 7 Review

14. A 80-dB sound carries more energy than a 40-dB sound by a factor of

D. 10,000.

56. A medal in a plastic cube whose index of refraction is 1.5 appears to be 20 mm below the upper surface of the cube. The depth of the medal is actually

D. 30 mm.

16. The wavelength of the wave shown in the figure is

D. D.

1.In a transverse wave, the individual particles of the medium move

D. perpendicular to the direction of travel.

44. When the American flag is viewed with red light it appears

D. red and black.

47. The setting sun appears red because its light is

D. scattered.

6. Sound waves travel fastest in

D. solids.

24. Of the following kinds of waves, the ones that cannot travel through a vacuum are

D. sound waves.

28. Of the following kinds of waves, those that cannot be polarized are

D. sound waves.

50. Sound waves of frequency 300 Hz have a speed relative to sound waves in the same medium of frequency 600 Hz that is

B. the same.

7. The higher the frequency of a wave,

B. the shorter its wavelength.

10. A pure musical note causes a thin wooden panel nearby to vibrate with the same frequency. This is an example of

10. A pure musical note causes a thin wooden panel nearby to vibrate with the same frequency.

17. Two waves meet at a time when one has the instantaneous amplitude A and the other has the instantaneous amplitude B. Their combined amplitude at this time is

A. A + B.

22. A frequency that is not an overtone of the fundamental frequency F is

A. F/2.

23. A changing electric field gives rise to

A. a magnetic field.

37. The image a camera lens forms on the film or sensor is

A. always real.

32. A converging lens of focal length f produces a virtual image of a real object when the object is

A. closer than f from the lens.

8. Ultrasound refers to sound whose

A. frequency is too high for most people to hear.

18. A wave of amplitude A interferes with another wave of the same kind with the same frequency whose amplitude is also A. The resulting wave

A. has an amplitude of 2A.

31. You are looking at the bottom of a lake 1.2 m deep from a boat. To you the lake seems to be

A. less than 1.2 m deep.

5. The amplitude of a sound wave determines its

A. loudness.

40. Light of which of the following colors has the longest wavelength?

A. red

29. The ionosphere

A. reflects radio waves.

51. Ocean waves with a period of 10 s are found to have a wavelength of 120 m. Their speed is

B. 12 m/s.

55. The speed of light in a transparent plastic whose index of refraction is 1.5 is

B. 2 × 108 m/s.

53. Radio amateurs are permitted to communicate on the "10-meter band." What frequency of radio waves corresponds to a wavelength of 10 meters? The speed of radio waves is 3 × 108 m/s.

B. 3.0 × 107 Hz

27. Polarization is similar to

D. None of the choices are correct.

48. To an astronaut in orbit around the earth the sky appears

D. black.

30. Of the following, the highest index of refraction is found in

D. diamond.

25. Which of the following is not a property of an electromagnetic wave?

D. electric charge

4. When waves go from one place to another, they carry

D. energy.

41. The property of light waves that leads to the phenomenon of color is

D. frequency.

35. When a real object is the distance f from a converging lens,

D. no image is formed.

54. A boat at anchor is rocked by waves whose crests are 50 m apart and whose speed is 10 m/s. These waves reach the boat once every

B. 5 s.

15. The amplitude of the wave shown in the figure is

B. B.

21. Relative to the radio signals sent out by a spacecraft headed away from the earth, the signals that are received on the earth have

B. a lower frequency.

39. Light of which of the following colors has the highest frequency?

B. blue

46. Light of which of the following colors is scattered most in the atmosphere?

B. blue

12. A sound wave whose frequency is 50 Hz

B. has a relatively long wavelength.

36. Relative to its object, a real image formed by a lens is always

B. inverted.

26. In an electromagnetic wave, the electric field is

B. perpendicular to both the magnetic field and the wave direction.

20. Which one of the following effects does not occur in all types of wave?

B. polarization

38. The image the lens of the eye forms on the retina is

B. real and inverted.

52. The musical note A has a frequency of 440 Hz and its wavelength in seawater is 3.5 m. The speed of sound in seawater is

C. 1540 m/s.

11. The wavelength of a sound wave is not related to its

C. amplitude.

43. The Swedish flag is blue and yellow. When viewed with blue light it appears

C. blue and black.

19. The bending of waves around the edge of an obstacle in their path is an example of

C. diffraction.

33. A converging lens of focal length f produces a real image of a real object when the object is

C. farther than f from the lens.

9. When a sound wave goes from air into water, the quantity that remains unchanged is its

C. frequency.

42. Relative to the focal length of a wide-angle camera lens, the focal length of a telephoto lens is

C. longer.

13. The greater the decibel (dB) level of a sound wave, the

C. louder it is.

49. Sound waves of frequency 300 Hz have a wavelength relative to sound waves in the same medium of frequency 600 Hz that is

C. twice as great.

3. An example of a wave that is partly longitudinal and partly transverse is a

C. water wave.

2. An example of a purely longitudinal wave is a

A. sound wave.

45. Dispersion is the term used to describe the

A. splitting of white light into its component colors in refraction.

34. The image formed by a diverging lens of a real object is always which of the following?

A. virtual