Waves propagate along a stretched string with a speed of 8 m/s. The end of the string is vibrated up and down once every 1.5 s. What is the wavelength of the waves that travel along the string?
a) 3.0 m b) 12.0 m c) 6.0 m d) 5.33 m
Bats can detect small objects such as insects that are of a size approximately that of one wavelength. If bats emit a chirp at a frequency of 60 kHz, and the speed of soundwaves in air is 330 m/s, what is the smallest size insect they can detect?
a) 1.5 mm b) 3.5 mm c) 5.5 mm d) 7.5 mm
4/18/2016
If the frequency of a traveling wave train is increased by a factor of three in a medium where the velocity is constant, which of the following is the result?
a) amplitude is one-third as big b) amplitude is tripled c) wavelength is one-third as big d) wavelength is tripled
As a gust of wind blows across a field of grain, a wave can be seen to move across the field as the tops of the plants sway back and forth. This wave is a a) transverse wave b) longitudinal wave c) polarized wave d) interference of waves
a) the distance between crests.
b) the height difference between a crest and a trough.
c) one-half the height difference between a crest and a trough.
d) how far the wave goes up on the beach.
A radio wave has a speed of 3 x 10 8 m/s and a frequency of 107.7 MHz. What is its wavelength?
a) 3.21 m b) 45.0 m c) 0.10 m d) 2.78 m
1

A 2-m long piano string of mass 10 grams is under a tension of 338 N. Find the velocity with which a wave travels on this string.
a) 130 m/s b) 260 m/s c) 520 m/s d) 1040 m/s
Transverse waves travel with a speed of 200 m/s along a taut copper wire that has a diameter of 1.5 mm. What is the tension in the wire? (The density of copper is 8.93 grams/cm 3 .) a) 1893 N b) 1262 N c) 631 N d) 315 N
4/18/2016
The tension in a guitar string is increased by a factor of two. By what factor does the wave velocity change?
a) 2.0
b) 1.4
c) 0.7
d) 0.5
Tripling the tension in a guitar string will result in changing the wave velocity in the string by what factor?
a) 0.58
b) 1.00
c) 1.73
d) 3.00
Tripling the density, in mass per unit length, of a guitar string will result in changing the wave velocity in the string by what factor?
a) 0.58
b) 1.00
c) 1.73
d) 3.00
The sound intensity 5.0 m from a point source is
0.50 W/m 2 .The power output of the source is: a. 39 W b. 160 W c. 266 W d. 320 W e. 390 W
2

The intensity of sound wave A is 100 times that of sound wave B. Relative to wave B the sound level of wave A is: a. - 2 db b. +2 db c. +10 db d. +20 db e. +100 db
The intensityof a certain sound wave is 6
µW/cm 2 . If its intensity is raised by 10 dB, the new intensity(in µW/cm 2 ) is: a. 60 b. 6.6
c. 6 .06
d. 600 e. 12
4/18/2016
The sound level at a point P is 14 dB below the sound level at a point 1.0 m from a point source. The distance from the source to point P is: a. 4.0 cm b. 202 m c. 2.0 m d. 5.0 m e. 25 m
Two pulses on a string approach each other at speeds of 1 m/s. What is the shape of the string at t = 6 s?
(1) (2) (3) (4)
An open-open tube of air supports standing waves at frequencies of 300 Hz and 400 Hz, and at no frequencies between these two. The second harmonic of this tube has frequency
1. 800 Hz.
2. 600 Hz.
3. 400 Hz.
4. 200 Hz.
5. 100 Hz.
Two loudspeakers emit waves with λ = 2.0 m.
Speaker 2 is 1.0 m in front of speaker 1.
What, if anything, must be done to cause constructive interference between the two waves?
1. Move speaker 1 backward (to the left) 0.5 m.
2. Move speaker 1 backward (to the left) 1.0 m.
3. Move speaker 1 forward (to the right) 1.0 m.
4. Move speaker 1 forward (to the right) 0.5 m.
5. Nothing. The situation shown already causes constructive interference.
3

What is the phase difference when two waves, traveling in the same medium, undergo constructive interference?
a) 270° b) 180° c) 90° d) 0°
These two loudspeakers are in phase. They emit equal-amplitude sound waves with a wavelength of
1.0 m. At the point indicated, is the interference maximum constructive, perfect destructive or something in between?
1. maximum constructive
2. perfect destructive
3. something in between
You hear three beats per second when two sound tones are generated. The frequency of one tone is known to be 610 Hz. The frequency of the other is
1. 604 Hz.
2. 607 Hz.
3. 613 Hz.
4. 616 Hz.
5. Either 2 or 3.
There are some points on a standing wave that never move. What are these points called?
1. Harmonics
2. Normal Modes
3. Nodes
4. Anti-nodes
5. Interference
4/18/2016
Two sound waves of nearly equal frequencies are played simultaneously. What is the name of the acoustic phenomena you hear if you listen to these two waves?
1. Beats
2. Diffraction
3. Harmonics
4. Chords
5. Interference
The various possible standing waves on a string are called the
1. antinodes.
2. resonant nodes.
3. normal modes.
4. incident waves.
4

The frequency of the third harmonic of a string is
1. one-third the frequency of the fundamental.
2. equal to the frequency of the fundamental.
3. three times the frequency of the fundamental.
4. nine times the frequency of the fundamental.
4/18/2016
5