 Download Download Presentation 0.7 Hz 1.0 Hz 1.4 Hz 2.0 Hz

# 0.7 Hz 1.0 Hz 1.4 Hz 2.0 Hz

Download Presentation ## 0.7 Hz 1.0 Hz 1.4 Hz 2.0 Hz

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1. A 100-m long high-voltage cable is suspended between two towers. The mass of the 100-m cable is 150 kg. If the tension in the cable is 30,000 N, what is the lowest frequency at which this cable can oscillate? • 0.7 Hz • 1.0 Hz • 1.4 Hz • 2.0 Hz

2. A standing wave is set up in a 200 cm length string fixed at both ends. The string vibrates in 5 distinct segments when driven by a 120 Hz source. What is the wavelength? • 10 cm • 20 cm • 40 cm • 80 cm

3. Two loudspeakers are placed side by side and driven by the same source at 500 Hz. A listener is positioned in front of the two speakers and on the line separating them, thus creating a constructive interference at the listener's ear. If one of the speakers is gradually pushed toward the listener, how far must it be moved to repeat the condition of constructive interference at the listener's ear? (The speed of sound = 340 m/s) • 1.02 m • 0.68 m • 0.34 m • 0.17 m

4. A standing wave is set up in a 2.0 m length string fixed at both ends. The string vibrates in 5 distinct segments when driven by a 120 Hz source. What is the natural fundamental frequency of the string? • 24 Hz • 48 Hz • 240 Hz • 600 Hz

5. A standing wave is set up in a 2.0 m length string fixed at both ends. The string vibrates in 5 distinct segments when driven by a 120 Hz source. In how many distinct standing wave segments would the same string vibrate if the tension were increased by A factor of 4? • 3 • 10 • 20 • No standing wave pattern occurs.

6. If a 1000 Hz sound source moves at a speed of 50.0 m/s toward a listener who moves at a speed of 30.0 m/s in a direction away from the source, what is the apparent frequency heard by the listener? (The velocity of sound is 340 m/s.) • 937 Hz • 947 Hz • 1060 Hz • 1070 Hz

7. The density of a certain metal solid is 7.2 x 103 kg/m3 and its Young's modulus is 10 x 1010 N/m2 . What is the velocity of sound in this metal? • 1.4 x 107 m/s • 5900 m/s • 3700 m/s • 3000 m/s

8. If one-third of the members of a symphony orchestra are absent because of head colds, thus reducing the overall intensity of sound by 33%, what will be the reduction in the decibel level? • 30 dB • 3 dB • 48 dB • 1.7 dB

9. Two loudspeakers are placed next to each other and driven by the same source at 500 Hz. A listener is positioned in front of the two speakers and on the line separating them, thus creating a constructive interference at the listener's ear. What minimum distance would one of the speakers be moved back away from the listener to produce destructive interference at the listener's ear? (The speed of sound = 340 m/s) • 1.36 m • 0.68 m • 0.34 m • 0.17 m

10. If a sound source, with a 1000 Hz frequency, moves with a speed of 50.0 m/s toward a listener who is at rest, what is the apparent frequency as heard by the listener? (The velocity of sound = 340 m/s.) • 853 Hz • 872 Hz • 1150 Hz • 1170 Hz

11. What is the intensity of a sound with a measured intensity level of 84 dB? (I0 = 1012 watt/m2 ) • 8.4 x 10-3 watts/m2 • 2.5 x 10-4 watts/m2 • 1.2 x 10-5 watts/m2 • 7.4 x 10-4 watts/m2

12. If the distance between a point sound source and a dB detector is increased by a factor of 4, what will be the reduction in intensity level? • 16 dB • 12 dB • 4 dB • 0.5 dB

13. The speed of sound at 0°C is 331 m/s. What is the speed of sound at 25°C? (0°C = 273 K) • 346 m/s • 356 m/s • 343 m/s • 350 m/s

14. When you are standing by the railroad tracks, a train passes by. The 1000 Hz frequency you hear on approach changes to 800 Hz as it goes away. How fast is the train moving? (The velocity of sound = 340 m/s.) • 15.67 m/s • 21.17 m/s • 28.0 m/s • 37.78 m/s

15. What is the intensity level of a sound with intensity of 5 x 1010 watts/m2 ? (I0 = 1012 watt/m2 ) • 74 dB • 54 dB • 2.7 dB • 27 dB

16. Tripling the tension in a guitar string will change its natural frequency by what factor? • 0.58 • 1.0 • 1.7 • 3.0

17. Tripling the mass per unit length of a guitar string will change its natural frequency by what factor? • 0.58 • 1.0 • 1.7 • 3.0

18. The lower A on a piano has a frequency of 27.5 Hz. If the tension in the 2-m long string is 304 N and one-half wavelength occupies the string, what is the mass of the string? • 100 grams • 25 grams • 37 grams • 50 grams

19. A vibrating guitar string emits a tone simultaneously with one from a 500 Hz tuning fork. If a beat frequency of 5 Hz results, what is the frequency of vibration of the string? • 505 Hz • 495 Hz • Both 505 Hz and 495 Hz are valid. • 2500 Hz

20. What is the lowest frequency that will resonate in a 2 m length organ pipe, closed at one end? The speed of sound in air is 340 m/s. • 42.5 Hz • 85 Hz • 170 Hz • 680 Hz

21. What is the first overtone frequency for a 2 m length organ pipe, closed at one end? The speed of sound in air is 340 m/s. • 42.5 Hz • 85 Hz • 127 Hz • 680 Hz

22. If a guitar string has a fundamental frequency of 500 Hz, what is the frequency of its second overtone? • 250 Hz • 750 Hz • 1000 Hz • 1500 Hz

23. Two vibrating tuning forks, held side by side, will create a beat frequency of what value if the individual frequencies of the two forks are 342 Hz and 345 Hz, respectively? • 687 Hz • 343.5 Hz • 339 Hz • 3 Hz

24. A train station bell gives off a fundamental tone of 500 Hz as the train approaches the station at a speed of 20 m/s. If the velocity of sound in air is 335 m/s, what will be the apparent frequency of the bell to an observer riding the train? • 532 Hz • 530 Hz • 470 Hz • 472 Hz

25. A standing wave set up in a 2.5 m long organ pipe, open at both ends, will have a fundamental tone with what wavelength? • 1.25 m • 2.5 m • 5.0 m • 6.25 m

26. When a sound wave moves through a medium such as air, the motion of the molecules making up the medium is in what direction with respect to the motion of the sound wave? • parallel • anti-parallel • both parallel and anti-parallel are valid. • perpendicular

27. The velocity of sound in air is a function of which one of the following? • wavelength • frequency • temperature • amplitude

28. Doubling the power output from a sound source emitting a single frequency will result in what increase in loudness? • 0.5 dB • 2.0 dB • 3.0 dB • 20 dB

29. Tripling the distance between sound source and a listener will change the intensity, as detected by the listener, by what factors? • 1/9 • 0.33 • 3.0 • 9.0

30. A sound wave with a speed of 334 m/s and a wavelength of 3.0 m has what frequency? • 1000 Hz • 337 Hz • 111 Hz • 1/111 Hz

31. The trough of the sine curve used to represent a sound wave corresponds to which of the below? • condensation • rarefaction • point where molecules vibrate at a right angle to the direction of wave travel • region of low elasticity

32. A series of ocean waves, each 5.0 m from crest to crest, moving past the observer at a rate of 2 waves per second, have what velocity? • 2.5 m/s • 5.0 m/s • 8.0 m/s • 10.0 m/s

33. If the tension on a guitar string is increased by a factor of 3, the fundamental frequency at which it vibrates is changed by what factor? • 9 • 3 • √3 • 1/ √3

34. What phenomenon is created by two tuning forks, side by side, emitting frequencies which differ by only a small amount? • resonance • interference • the Doppler effect • beats

35. The number of overtones, and their relative intensities, is associated with what property of the tone generated by a musical instrument? • quality • interference pattern • range • attack pattern

36. The Doppler shift of ultrasonic waves can measure the velocity of blood in an artery. If the frequency of the stationary source is 100 kHz and the reflected sound has a Doppler shift of 200 Hz, what is the blood flow speed? (The speed of sound in the body is 1500 m/s.) • 1.0 m/s • 1.5 m/s • 2.2 m/s • 3.3 m/s

37. A bat, flying at 5 m/s, emits a chirp at 50 kHz. If this sound pulse is reflected by a wall, what is the frequency of the echo received by the bat? (Vsound = 340 m/s2 ) • 51.5 kHz • 51.2 kHz • 40.8 kHz • 50.5 kHz

38. A very loud train whistle has an acoustic power output of 100 Watts. If the sound energy spreads out spherically, what is the intensity level in dB at a distance of 100 meters from the train? (I0 = 10-12 W/m2 ) • 78.3 dB • 81.6 dB • 89.0 dB • 95.0 dB

39. How far away is a lightning strike if you hear the thunderclap 3 s after you see the lightning bolt strike? (Vsound = 340 m/s, Vlight = 3 x 108 m/s) • 113 m • 340 m • 680 m • 1020 m

40. A low C (f = 65 Hz) is sounded on a piano. If the length of the piano wire is 2 m and its mass density is 5 g/m, what is the tension of the wire? • 84 N • 168 N • 338 N • 677 N

41. What is the intensity of sound (in W/m2 ) from a rock band with a sound level of 120 dB? (I0 = 10-12 W/m2 ) • 1 W/m2 • 1.2 W/m2 • 10W/m2 • 12W/m2

42. In the afternoon, the decibel level of a busy freeway is 80 dB with 100 cars passing a given point every minute. Late at night, the traffic flow is only 5 cars per minute. What is the late-night decibel level? • 77 dB • 74 dB • 70 dB • 67 dB

43. The intensity level of sound 20 m from a jet airliner is 120 dB. At what distance from the airplane will the sound intensity level be at a tolerable level of 100 dB? (Assume spherical spreading of sound.) • 90 m • 120 m • 150 m • 200 m

44. A flute behaves like a tube open at both ends. If its length is 65.3 cm, and the velocity of sound is 340 m/s, what is its fundamental frequency in Hz? • 130 Hz • 159 Hz • 212 Hz • 260 Hz

45. I stretch a rubber band and "plunk" it to make it vibrate in its fundamental frequency. I then stretch it to twice its length and make it vibrate in the fundamental frequency once again. If the rubber band is made so that doubling its length doubles the tension and reduces the mass per unit length by a factor of 2, the new frequency will be related to the old frequency by what factor? • 1.0 • 1.4 • 2.0 • 4.0

46. If two adjacent frequencies of an organ pipe closed at one end are 550 Hz and 650 Hz, what is the length of the organ pipe? (vsound = 340 m/s) • 0.85 m • 1.25 m • 1.50 m • 1.70 m

47. For a standing wave in an air column in a pipe that is open at both ends, there must be at least • one node and one antinode • two nodes and one antinode • two antinodes and one node • two nodes and two antinodes

48. Two notes have a beat frequency of 4 Hz. The frequency of one note is 420 Hz. What is the frequency of the other note? • 422 Hz or 418 Hz • 105 Hz • 424 Hz or 416 Hz • 1680 Hz

49. While standing at a crosswalk, you hear a frequency of 560 Hz from an approaching police car. After the police car passes, its frequency is 480 Hz. Given the speed of sound is 340 m/s, what is the velocity of the police car? • 13.2 m/s • 17.4 m/s • 21.1 m/s • 26.4 m/s

50. As a train starts from rest and then accelerates down the track, coming toward me faster and faster, the speed of the sound waves coming toward me will be • slower than the normal speed of sound in air. • equal to the normal speed of sound in air. • some constant speed faster than the normal speed of sound in air. • faster and faster.