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Name
Class
Date
Assessment
Chapter Test A
Sound
M ULTIPLE CHOICE
In the space provided, write the letter of the term or phrase that best completes
each statement or best answers each question.
______ 1. Sound waves
a. are a part of the electromagnetic spectrum.
b. do not require a medium for transmission.
c. are longitudinal waves.
d. are transverse waves.
______ 2. The trough of the sine curve used to represent a sound wave
corresponds to a
a. compression.
b. region of high pressure.
c. point where molecules are pushed closer together.
d. rarefaction.
______ 3. Which of the following is the region of a sound wave in which the
density and pressure are greater than normal?
a. rarefaction
c. amplitude
b. compression
d. wavelength
______ 4. The highness or lowness of a sound is perceived as
a. compression.
c. ultrasound.
b. wavelength.
d. pitch.
______ 5. Pitch depends on the
a. frequency
b. amplitude
of a sound wave.
c. power
d. speed
______ 6. In general, sound travels faster through
a. solids than through gases.
b. gases than through solids.
c. gases than through liquids.
d. empty space than through matter.
______ 7. At a large distance from a sound source, spherical wave fronts are
viewed as
a. wavelengths.
c. rays.
b. troughs.
d. plane waves.
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Chapter Test
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Chapter Test A continued
______ 8. The distance between wave fronts of plane waves corresponds to
of a sound wave.
a. one wavelength
c. one compression
b. two amplitudes
d. one rarefaction
______ 9. A train moves down the track toward an observer. The sound from the
train, as heard by the observer, is
the sound heard by
a passenger on the train.
a. the same as
c. higher in pitch than
b. a different timbre than
d. lower in pitch than
______10. The Doppler effect occurs with
a. only sound waves.
b. only transverse waves.
c. only water waves.
d. all waves.
______11. The property of sound called intensity is proportional to the rate at
which energy flows through
a. an area perpendicular to the direction of propagation.
b. an area parallel to the direction of propagation.
c. a cylindrical tube.
d. a sound wave of a certain frequency.
______12. The perceived loudness of a sound is measured in
a. hertz.
c. watts.
b. decibels.
d. watts per square meter.
______13. Which of the following decibel levels is nearest to the value that you
would expect for a running vacuum cleaner?
a. 10 dB
c. 70 dB
b. 30 dB
d. 120 dB
______14. A sound twice the intensity of the faintest audible sound is not perceived as twice as loud because the sensation of loudness in human
hearing
a. is approximately logarithmic.
b. is approximately exponential.
c. depends on the speed of sound.
d. is proportional to frequency.
______15. When the frequency of a force applied to a system matches the natural
frequency of vibration of the system,
occurs.
a. damped vibration
c. timbre
b. random vibration
d. resonance
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TEACHER RESOURCE PAGE
Solution
A single loop (antinode) is produced by
a wavelength equal to 2L. Two loops
(one complete wavelength) are produced by a wavelength of L. A wavelength of 2/3 L results in 3 antinodes.
The following pattern emerges:
1 loop l ⫽ 2L/1 ⫽ 2L
2 loops l ⫽ 2L/2 ⫽ L
3 loops l ⫽ 2L/3 ⫽ 2/3 L
4 loops l ⫽ 2L/4 ⫽ 1/2 L
5 loops l ⫽ 2L/5 ⫽ 2/5 L
2/5 ⫻ 2.0 m ⫽ 0.80 m
Sound
CHAPTER TEST A (GENERAL)
1. c
11. a
2. d
12. b
3. b
13. c
4. d
14. a
5. a
15. d
6. a
16. a
7. d
17. c
8. a
18. c
9. b
19. b
10. d
20. a
21. compression
22. frequency
23. watts per square meter, or W/m2
24. Resonance occurs when the frequency
of a force applied to an object is the
same as the natural frequency of an
object.
25. 547 Hz
Given
v ⫽ 684 m/s
L ⫽ 62.5 cm
Solution
v
fn ⫽ nᎏᎏ
2L
At the fundamental frequency (first
harmonic), n ⫽ 1, so
v
684 m/s
f1 ⫽ ᎏᎏ ⫽ ᎏᎏ ⫽ 547 Hz
2L
2(0.625 m)
Sound
CHAPTER TEST B (ADVANCED)
1. c
8. c
2. b
9. c
3. c
10. c
4. c
11. d
5. a
12. d
6. c
13. b
7. d
14. longitudinal
15. rarefaction
16. The pitch rises.
17. As a sphere increases in radius, sections of its surface approach a plane
surface. A plane wave is a section of a
spherical wave that has such a large
radius that sections of it appear planar. This condition appears when the
observer of the wave is at a large distance from the source.
18. The apparent pitch of the sound drops
as the ambulance passes.
19. The distance from the source doubles,
so the intensity decreases to onefourth of its value at the 10 m distance. The intensity is inversely
proportional to the square of the
distance from the source, or intensity
⬀1/r2.
20. One of the musical sounds from the
CD matches the natural frequency of
the string in the piano. As a result, the
energy of the sound wave causes the
string to vibrate in resonance with the
note from the CD.
21. If the musical note is at the fundamental frequency of the glass, the glass
will absorb energy from the sound
waves and vibrate in resonance with
the note. If the sound is loud enough,
the vibration will overcome the
strength of the glass and the goblet
will shatter.
22. 9.3 ⫻ 10⫺3 W/m2
Given
P ⫽ 0.30 W
r ⫽ 1.6 m
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Chapter Test