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1.	The intensity of a sound decreases by a factor of 4. As aresult, the sound intensity level decreases by ______.
	4 dB 16 dB 6 dB 8 dB
2.	The human threshold of pain is about how many decibels?
	80 dB 140 dB 100 dB 120 dB

3.	Two sinusoidal sound waves with slightly different frequenciescombine to form a third sound wave called a beat. How does theamplitude of the beat change over time, or does it remainconstant?
	The amplitude increases and decreases in a sinusoidalpattern. The amplitude increases indefinitely. The amplitude remains constant. The amplitude changes in a pattern of a steady increase, then asudden decrease.
4.	Two audio speakers produce, in step, the same sinusoidal soundof wavelength λ. A listening device is positioned at point Q in theroom and registers no sound from the speakers. What characterizesthe two sound waves as they arrive at point Q? Assume the room isanechoic (produces no echoes.)
	One wave has twice the amplitude of the other wave. The two waves are a half-cycle out of step. One wave has twice the frequency of the other wave. The two waves are a full cycle out of step.

5.	At an auto race, a member of the pit crew stands beside thetrack. A car approaches him at 110 m/s and emits a sound atfrequency 1200 Hz. The air is still and the speed of sound is340m/s. What frequency will the pit crew member hear?
	907 Hz 811 Hz 1590 Hz 1770 Hz
6.	The frequency of the faintest audible sound is about 1,000 Hz.What is the pressure variation corresponding to this sound?
	3 x 10-5 Pa 30 Pa 5 x 10-2 Pa 1 x 10-12 Pa

7.	Two loudspeakers are placed 4.5 m apart. They produce the samesounds, in step, across a frequency range of 744 Hz to 992Hz PointP is located 5.30m from one loudspeaker and 3.60m from the other.What frequency of sound from the two speakers will producedestructive interference at point P? Assume the speed of sound is344m/s
	971 Hz 890 Hz 931 Hz 911 Hz 951 Hz
8.	Two loudspeakers are placed 6.0 m apart. They produce the samesounds, in step, across a frequency range of 252Hz to 665Hz Point Pis located 5.10m from one loudspeaker and 3.60m from the other.What frequency of sound from the two speakers will produceconstructive interference at point P? Assume the speed of sound is344m/s
	573 Hz 459 Hz 631 Hz 401 Hz 516 Hz