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- 1. Multiple-choice2 minutes1 pt
A sound wave is different than a light wave in that a sound wave is:
A. Produced by an oscillating object and a light wave is not.
B. Not capable of traveling through a vacuum.
C. Not capable of diffracting and a light wave is.
D. Capable of existing with a variety of frequencies and a light wave has a single frequency.
- 2. Multiple-choice2 minutes1 pt
A sound wave is a pressure wave; regions of high (compressions) and low pressure (rarefactions) are established as the result of the vibrations of the sound source. These compressions and rarefactions result because sound
A. Is denser than air and thus has more inertia, causing the bunching up of sound.
B. Waves have a speed that is dependent only upon the properties of the medium.
C. Is like all waves; it is able to bend into the regions of space behind obstacles.
D. Is able to reflect off fixed ends and interfere with incident waves
E. Vibrates longitudinally; the longitudinal movement of air produces pressure fluctuations.
- 3. Multiple-choice2 minutes1 pt
In the storming night, you will always see the lightning first, then hear the thunder after. When the lightning is 5 seconds ahead of the thunder, how far the cloud is way from you? (The speed of light is 3.0×108 m/s, the speed of sound is 343 m/s)
500 m
1000 m
1700 m
2000 m
- 4. Multiple-choice2 minutes1 pt
Two musical notes that have a frequency ratio of 2:1 are said to be separated by an octave. A musical note that is separated by an octave from middle C (262 Hz) has a frequency of _____. (There could be more than one correct choice.)
A. 131 Hz
B. 254 Hz
C. 270 Hz
D. 524 Hz
E. None of these above
- 5. Multiple-choice2 minutes1 pt
The sound level near a noisy air conditioner is 70 dB. If two such units operate side by side, the sound level near them would be
(a) 70 dB.
(b) 73 dB.
(c) 105 dB.
(d) 140 dB.
- 6. Multiple-choice2 minutes1 pt
A trumpeter plays at a sound level of 75 dB. Three equally loud trumpet players join in. What is the new sound level?
A. 78 dB.
B. 81 dB
C. 225 dB
D. None of the above
- 7. Multiple-choice2 minutes1 pt
A mosquito's buzz is often rated with a decibel rating of 40 dB. Normal conversation is often rated at 60 dB. How many times more intense is normal conversation compared to a mosquito's buzz?
A. 2
B. 20
C. 100
D. 200
E. 400
- 8. Multiple-choice2 minutes1 pt
On a good night, the front row of the Twisted Sister concert would surely result in a 120 dB sound level. An IPod produces 90 dB. How many IPods would be needed to produce the same intensity as the front row of the Twisted Sister concert?
A. 3
B. 30
C. 100
D. 1000
E. 3000
- 9. Multiple-choice2 minutes1 pt
Two speakers are arranged so that sound waves with the same frequency are produced and radiate through the room. An interference pattern is created (as represented in the diagram at the right). The thick lines in the diagram represent wave crests and the thin lines represent wave troughs. At which of the labeled point(s) would constructive interference occur?
A. B only
B. A, B, and C
C. D, E, and F
D. A and B
- 10. Multiple-choice2 minutes1 pt
A tuning fork with a frequency of 440 Hz is played simultaneously with a fork with a frequency of 437 Hz. How many beats will be heard over a period of 10 seconds?
3
15
30
300
- 11. Multiple-choice2 minutes1 pt
When a sound wave passes from air into water, what properties of the wave will change?
(a) Frequency only
(b) Wavelength only
(c) Wave speed only
(d) Both frequency and wavelength.
(e) Both wave speed and wavelength.
- 12. Multiple-choice2 minutes1 pt
Two loudspeakers are about 10 m apart in the front of a large classroom. If either speaker plays a pure tone at a single frequency of 400 Hz, the loudness seems pretty even as you wander around the room, and gradually decreases in volume as you move farther from the speaker. If both speakers then play the same tone together, what do you hear as you wander around the room? (Think about interference of two loudspeakers)
(a) The pitch of the sound increases to 800 Hz, and the sound is louder but not twice as loud. It is louder closer to the speakers and gradually decreases as you move away from the speakers—except near the back wall, where a slight echo makes the sound louder.
(b) The sound is louder but maintains the same relative spatial pattern of gradually decreasing volume as you move away from the speakers.
(c) As you move around the room, some areas seem to be dead spots with very little sound, whereas other spots seem to be louder than with only one speaker.
(d) The sound is twice as loud—so loud that you cannot hear any difference as you move around the room.
(e) At points equidistant from both speakers, the sound is twice as loud. In the rest of the room, the sound is the same as if a single speaker were playing.
- 13. Multiple-choice2 minutes1 pt
You are driving at 75 km/h. Your sister follows in the car behind at 75 km/h. When you honk your horn, your sister hears a frequency
(a) higher than the frequency you hear.
(b) lower than the frequency you hear.
(c) the same as the frequency you hear.
(d) You cannot tell without knowing the horn’s frequency.
- 14. Multiple-choice5 minutes1 pt
A string that is 0.67 m long is under tension. The string vibrates at 700 Hz tone in its third harmonic, and this vibration causes a sound wave. What is the wavelength of the sound in the air? The speed of sound in air is 344 m/s.
0.67 m
0.45 m
0.55 m
0.61 m
0.49 m
- 15. Multiple-choice5 minutes1 pt
An organ pipe open at both ends has a length of 0.80 m. If the velocity of sound in air is 340 m/s, what is the frequency of the second harmonic of this pipe?
850 Hz
213 Hz
638 Hz
425 Hz
- 16. Multiple-choice5 minutes1 pt
One of the harmonics of an air column in a tube that is open at both ends has a frequency of 448 Hz, and the next higher harmonic has a frequency of 576 Hz. What is the fundamental frequency of the air column in this tube?
32 Hz
64 Hz
128 Hz
256 Hz
88 Hz
- 17. Multiple-choice5 minutes1 pt
One of the harmonics of an air column in a tube that is open at one end and closed at the other has a frequency of 448 Hz, and the next higher harmonic has a frequency of 576 Hz. What is the fundamental frequency of the air column in this tube?
128 Hz
64 Hz
256 Hz
32 Hz
88 Hz
