Chapter 15: Wave Motion

1. Chapter 15: Wave Motion Section 15-1: Simple Wave Motion

2. Which of the following statements is true? • Waves transmit energy but not matter. • Waves transmit matter but not energy. • Waves transmit both energy and matter.

3. Which of the following statements is true? • Waves transmit energy but not matter. • Waves transmit matter but not energy. • Waves transmit both energy and matter.

4. During the passage of a longitudinal wave, a particle of the medium • remains in a fixed position. • moves in a circle. • moves at right angles to the direction of propagation. • moves forward and backward along the line of propagation.

5. During the passage of a longitudinal wave, a particle of the medium • remains in a fixed position. • moves in a circle. • moves at right angles to the direction of propagation. • moves forward and backward along the line of propagation.

6. A longitudinal wave is distinguished from a transverse wave by the fact that in longitudinal waves • the particle vibration is parallel to the direction of propagation. • the particle vibration is perpendicular to the direction of propagation. • energy is transported from one point in space to another point. • vibrations occur only in air or water.

7. A longitudinal wave is distinguished from a transverse wave by the fact that in longitudinal waves • the particle vibration is parallel to the direction of propagation. • the particle vibration is perpendicular to the direction of propagation. • energy is transported from one point in space to another point. • vibrations occur only in air or water.

8. A particle in a medium is part of a wave motion. Its maximum distance from the equilibrium position is called its • amplitude • displacement • phase • wavelength • period

9. A particle in a medium is part of a wave motion. Its maximum distance from the equilibrium position is called its • amplitude • displacement • phase • wavelength • period

10. In which of the following is the speed of sound greatest? • air • water • a vacuum • wood • steel

11. In which of the following is the speed of sound greatest? • air • water • a vacuum • wood • steel

12. A string under tension carries transverse waves traveling at speed v. If the same string is under four times the tension, what is the wave speed? • Increased v • Decreased v

13. A string under tension carries transverse waves traveling at speed v. If the same string is under four times the tension, what is the wave speed? • Increased v • Decreased v

14. A string under tension carries a transverse wave traveling at speed v. If the density of the string is doubled, what is the wave speed? • Increased v • Decreased v

15. A string under tension carries a transverse wave traveling at speed v. If the linear density of the string is doubled, what is the wave speed? • Increased v • Decreased v

16. Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air, • the frequency remains the same but the wavelength is shorter. • the frequency remains the same but the wavelength is longer. • the frequency is lower and the wavelength remains the same. • the frequency is higher and the wavelength remains the same. • both the frequency and the wavelength remain the same.

17. Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air, • the frequency remains the same but the wavelength is shorter. • the frequency remains the same but the wavelength is longer. • the frequency is lower and the wavelength remains the same. • the frequency is higher and the wavelength remains the same. • both the frequency and the wavelength remain the same.

18. When the frequency of a source producing sound in air is doubled, the sound produced • travels at half its former speed. • travels at twice its former speed. • has half its former wavelength. • has twice its former wavelength. • is greatly improved in quality.

19. When the frequency of a source producing sound in air is doubled, the sound produced • travels at half its former speed. • travels at twice its former speed. • has half its former wavelength. • has twice its former wavelength. • is greatly improved in quality.

20. Chapter 15: Wave Motion Section 15-2: Periodic Waves

21. A traveling wave passes a point of observation. At this point, the time between successive crests is 0.2 s. Which of the following statements can be justified? • The wavelength is 5 m. • The frequency is 5 Hz. • The velocity of propagation is 5 m/s. • The wavelength is 0.2 m. • There is not enough information to justify any of these statements.

22. A traveling wave passes a point of observation. At this point, the time between successive crests is 0.2 s. Which of the following statements can be justified? • The wavelength is 5 m. • The frequency is 5 Hz. • The velocity of propagation is 5 m/s. • The wavelength is 0.2 m. • There is not enough information to justify any of these statements.

23. Electromagnetic waves • include light, radio waves, X rays, gamma rays, and microwaves. • do not require a medium for propagation. • travel through a vacuum with a speed of approximately 3  108 m/s. • are produced when free electrons accelerate. • are described by all of the above.

24. Electromagnetic waves • include light, radio waves, X rays, gamma rays, and microwaves. • do not require a medium for propagation. • travel through a vacuum with a speed of approximately 3  108 m/s. • are produced when free electrons accelerate. • are described by all of the above.

25. We can hear sounds that are produced around a corner but cannot see light that is produced around a corner because • light travels only in straight lines whereas sound can travel in a curved path. • sound has more energy than light. • sound has shorter wavelengths than light. • sound has longer wavelengths than light. • None of these is correct.

26. We can hear sounds that are produced around a corner but cannot see light that is produced around a corner because • light travels only in straight lines whereas sound can travel in a curved path. • sound has more energy than light. • sound has shorter wavelengths than light. • sound has longer wavelengths than light. • None of these is correct.

27. A cord stretched to a tension FT, consists of two sections of different densities (think spring and slinky.) A wave of frequency f and speed v is sent along the cord from one end. Which of the following statements is true about the transmitted and reflected waves? • Both the transmitted and reflected waves have the same speed, v. • Both the transmitted and reflected waves have the same frequency, f. • Both the transmitted and reflected waves have the same wavelength, l. • All of the above. • None of the above.

28. A cord stretched to a tension FT, consists of two sections whose linear densities are m1 and m2 (< m1). A wave of frequency f and speed v is sent along the cord from one end. Which of the following statements is true about the transmitted and reflected waves? • Both the transmitted and reflected waves have the same speed, v. • Both the transmitted and reflected waves have the same frequency, f. • Both the transmitted and reflected waves have the same wavelength, l. • All of the above. • None of the above.

29. When a dense fog blanket an area at night, you can often hear traffic noises coming from a distance highway or jets taking off from an airport several miles away. The reason is because • when it is foggy there are layers of air at different temperatures so that some sound waves are reflected at the interface rather than spreading in all directions. • when it is foggy, the air is still so you can hear sound better. • on foggy days or nights your hearing is more acute, to make up for the reduced visibility. • it is all in your head, it just seems that way. • None of the above.

30. When a dense fog blanket an area at night, you can often hear traffic noises coming from a distance highway or jets taking off from an airport several miles away. The reason is because • when it is foggy there are layers of air at different temperatures so that some sound waves are reflected at the interface rather than spreading in all directions. • when it is foggy, the air is still so you can hear sound better. • on foggy days or nights your hearing is more acute, to make up for the reduced visibility. • it is all in your head, it just seems that way. • None of the above.

31. A pulse moves in a string toward a free end (a ring on a post) as indicated in the sketch. On reflection, which sketch most nearly represents the pulse?

32. A pulse moves in a string toward a free end (a ring on a post) as indicated in the sketch. On reflection, which sketch most nearly represents the pulse?

33. The pulse shown is moving in the string toward a fixed end at the wall. After reflection at the wall, which figure correctly represents the pulse?

34. The pulse shown is moving in the string toward a fixed end at the wall. After reflection at the wall, which figure correctly represents the pulse?

35. From the figure, you can conclude that • the wave travels slower in the medium to the left of the interface than in the medium to the right of the interface. • the wave travels faster in the medium to the left of the interface than in the medium to the right of the interface. • the wave is traveling with the same speed on both sides of the interface.

36. From the figure, you can conclude that • the wave travels slower in the medium to the left of the interface than in the medium to the right of the interface. • the wave travels faster in the medium to the left of the interface than in the medium to the right of the interface. • the wave is traveling with the same speed on both sides of the interface.

37. The extent to which waves diffract when they encounter an obstacle or aperture depends on • the size of the aperture or obstacle. • the wavelength of the waves. • All of the above • None of the above.

38. The extent to which waves diffract when they encounter an obstacle or aperture depends on • the size of the aperture or obstacle. • the wavelength of the waves. • both of the above • none of the above.

39. Sketch A shows two identical pulses traveling in opposite directions along a string, each with a speed of 1.0 cm/s. After 4.0 s, the string will look like which of the other sketches? • 1 • 2 • 3 • 4 • 5

40. Sketch A shows two identical pulses traveling in opposite directions along a string, each with a speed of 1.0 cm/s. After 4.0 s, the string will look like which of the other sketches? • 1 • 2 • 3 • 4 • 5

41. Two wave trains of the same frequency are traveling in opposite directions down a string. When they meet, these wave trains will not • be described by the principle of superposition. • reflect from each other. • pass through one another. • continue to carry energy.

42. Two wave trains of the same frequency are traveling in opposite directions down a string. When they meet, these wave trains will not • be described by the principle of superposition. • reflect from each other. • pass through one another. • continue to carry energy.