Exam FORM A
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) A 0.663-m string is clamped at both ends. If the lowest standing wave frequency in the string is 326 Hz,
what is the wave speed?
A) 432 m/s
B) 536 m/s
C) 816 m/s
D) 657 m/s
2) The sound from a truck moving at 17.00 m/s reflects from a cliff and is heard by an observer on the truck.
What is the change in frequency for a wave with initial wavelength l = 0.1500 m? The speed of sound is
345 m/s in air.
A) 2450 Hz
B) 245 Hz
C) 206 Hz
D) 2281 Hz
3) Consider the waves on a vibrating guitar string and the sound waves the guitar produces in the
surrounding air. The string waves and the sound waves have the same
A) frequency.
B) velocity.
C) amplitude.
D) wavelength.
E) More than one of the above is true.
4) Which of the following is a FALSE statement?
A) Sound waves are mechanical in nature.
B) The speed of a wave and the speed of the vibrating particles that constitute the wave are different
entities.
C) A wave in which particles move back and forth in the same direction as the wave is moving is called a
longitudinal wave.
D) Waves transport energy and matter from one region to another.
E) In a transverse wave the particle motion is perpendicular to the velocity vector of the wave.
5) An organ pipe open at both ends has two successive harmonics with frequencies of 210 Hz and 240 Hz.
What is the length of the pipe? The speed of sound is 345 m/s in air.
A) 5.75 m
B) 4.90 m
C) 5.25 m
D) 3.62 m
E) 2.76 m
6) Two stereo speakers mounted 4.52 m apart on a wall emit identical sound waves. You are standing at the
opposite wall of the room at a point directly between the two speakers. You walk 2.11 m parallel to the
wall, to a location where you first notice that the sound intensity is much less. If the wall along which you
are walking is 8.3 m from the wall with the speakers, what is the wavelength of the sound waves?
A) 2.16 m
B) 3.67 m
C) 2.59 m
D) 3.24 m
7) Two motors in a factory are running at slightly different rates. If one runs at 825 rpm and the other at
787 rpm, how often will you hear the sound intensity increase due to wave interference?
A) 1.58 s
B) 1.83 s
C) 1.47 s
D) 1.71 s
8) The density of aluminum is 2700 kg/m3. If transverse waves propagate at 30 m/s in a 4.6-mm-diameter
aluminum wire, what is the tension on the wire?
A) 32 N
B) 48 N
C) 24 N
D) 40 N
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9) Consider the transverse vibrational wave on a stretched string. The energy transported by such a wave is
A) zero.
B) independent of the tension in the string.
C) proportional to the amplitude of the wave.
D) proportional to the square of the amplitude of the wave.
E) independent of the frequency of the wave.
10) One may readily deduce how sound intensity varies with distance from a uniformly radiating sound by
making use of
A) Newton's Laws of Motion.
B) the fact that sound is a longitudinal wave.
C) the Law of Conservation of Momentum.
D) the Law of Conservation of Energy.
E) the relation v = f l
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Answer Key
Testname: QUIZ1
1)
2)
3)
4)
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10)
A
B
A
D
A
A
A
D
D
D
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