Date
Period
15
Name
Study Guide
Use with Chapter 15.
Sound
Vocabulary Review
Copyright © by Glencoe/McGraw-Hill
Write the term that correctly completes each statement. Use each term once.
beat
dissonance
harmonic
sound level
consonance
Doppler shift
octave
timbre
decibel
fundamental
pitch
1.
The amplitude of sound, as measured on a logarithmic scale, is
called
.
2.
Any higher frequency that is a multiple of the fundamental frequency is a(n)
.
3.
An oscillation of wave amplitude caused by the sounding of two
nearly identical frequencies is called a(n)
.
4.
A unit used to measure sound level is the
.
5.
A jarring combination of pitches is called
.
6.
Two frequencies in a 1:2 ratio differ by a(n)
7.
The lowest frequency that will resonate in a pipe is the
8.
The apparent change in pitch caused by the motion of a sound
source is called the
.
9.
The apparent highness or lowness of a note, associated with frequency of vibration is called
.
10.
Tone color or tone quality is called
11.
A pleasant combination of pitches is called
Physics: Principles and Problems
.
.
.
.
Study Guide 85
15
Section 15.1:
Name
Study Guide
Properties of Sound
In your textbook, read about sound waves.
Write the term that correctly completes each statement.
Sound waves move in the same direction as the particles of the medium and are therefore
(1)
waves. The waves are caused by variations in
(2)
relating to the different (3)
of
molecules. Therefore, sound cannot travel through a(n) (4)
(5)
. The
of a sound wave is the number of pressure oscillations per second.
The (6)
is the distance between successive regions of high or low
pressure. The speed of a sound wave in air depends on the (7)
of the
air. At 20°C, sound moves through air at sea level at a speed of (8)
In general, the speed of sound is (9)
Reflected sound waves are (10)
m/s.
in liquids and solids than in gases.
. The reflection of sound waves can be
used to find the (11)
between a source and a reflecting surface.
Sound waves can (12)
, producing nodes, where little sound is heard.
Sound waves can also be (13)
; they spread outward after passing
through a narrow opening. The equation that relates velocity, frequency, and wavelength is
(14)
.
15. Sound level is measured on a logarithmic scale.
16. The ear detects pressure variations as sound.
17. Hearing loss can result from long exposure to dissonant sound levels.
18. Sound level is measured in hertz.
19. Loudness, as perceived by the human ear, is directly proportional to length of a pressure wave.
20. A 40-dB increase is perceived as roughly a doubling of the loudness of a sound.
86
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Physics: Principles and Problems
Copyright © by Glencoe/McGraw-Hill
In your textbook, read about loudness.
For each of the statements below, write true or rewrite the italicized part to make the statement true.
15
Name
Study Guide
In your textbook, read about sound waves and loudness.
For each term on the left, write the corresponding symbol from those on the right. Some symbols may be used
more than once.
21. period
dB
22. amplitude
Hz
23. speed
m
24. frequency
m/s
25. loudness
s
26. pitch
27. wavelength
In your textbook, read about pitch and the Doppler effect.
State whether the process would make the apparent pitch of a sound higher, lower, or have no effect on it.
28. moving the listener away from the sound source
29. decreasing the frequency
30. increasing the number of decibels
31. decreasing the wavelength, at constant wave speed
32. increasing the wavelength, at constant wave speed
33. moving the sound source toward the listener
34. decreasing the wave amplitude
35. increasing the wavelength, at constant frequency
Copyright © by Glencoe/McGraw-Hill
36. decreasing the period
In your textbook, read about the Doppler shift.
The drawing below shows the crests of sound waves produced by a
point source, S, that is moving. The two ears represent two listeners
at different positions. Refer to the drawing to answer the following
questions.
A
37. Which direction is the point source moving? Give a
reason for your answer.
S
38. How do the apparent wavelengths at A and B compare?
B
Physics: Principles and Problems
Study Guide 87
15
Name
Study Guide
39. How does the speed of the sound waves compare at A and B?
40. How does the apparent frequency at point A compare to that at point B? Give a reason for your
answer, in terms of the meaning of the word frequency and of the equation relating frequency to
speed and wavelength.
41. How loud is the sound heard at A compared to that heard at B when A and B are equally far from
the source? Give a reason for your answer.
42. Is the sound heard at A higher or lower pitch than that heard at B? Give a reason for your answer.
43. If the point source began to move faster in the same direction, would the apparent sound at A and
B change? If yes, how would it change?
45. Suppose B started to move downward while the point source continued to move in its original
direction. How would the apparent sound at B change, if at all?
88
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Physics: Principles and Problems
Copyright © by Glencoe/McGraw-Hill
44. If the point source stopped moving, how would the apparent sound at A and B change, if at all?
Name
15
Section 15.2:
Study Guide
The Physics of Music
In your textbook, read about pipe resonators and other sources of sound.
Circle the letter of the choice that best completes the statement or answers the question.
1. Sound is produced when there are
.
a. increases in pressure
c. increases in temperature
b. oscillations in pressure
d. electromagnetic waves
2. The frequencies of vibrating air that will be set into resonance are determined by an air column’s
.
a. radius
b. length
3. Resonance occurs when
c. mass
d. width
.
a. any constructive interference occurs
c. a standing wave is created.
b. any destructive interference occurs
d. no nodes are formed
4. In which kind of resonator is the pressure of the reflected wave inverted?
a. closed-pipe only
c. both open- and closed-pipe
b. open-pipe only
d. neither open- nor closed-pipe
5. In a standing sound wave in a pipe, nodes are regions of
.
a. maximum or minimum pressure and low displacement
b. maximum or minimum pressure and high displacement
c. mean atmospheric pressure and low displacement
d. mean atmospheric pressure and high displacement
Copyright © by Glencoe/McGraw-Hill
6. In a standing sound wave in a pipe, two antinodes are separated by
.
a. one-quarter wavelength
c. one-half wavelength
b. one wavelength
d. two wavelengths
In your textbook, read about resonance frequencies in pipes.
For each of the statements below, write true or false.
7. A closed pipe can’t have resonance unless it has antinodes at both ends.
8. In a closed pipe, a column of length /4 will be in resonance with a
tuning fork.
9. An open pipe can’t have resonance unless it has nodes at both ends.
10. In an open pipe, a column of length 3/4 will be in resonance with a
tuning fork.
11. For both open and closed pipes, resonance lengths are spaced at
half-wavelength intervals.
Physics: Principles and Problems
Study Guide 89
15
Name
Study Guide
In your textbook, read about sound detectors.
Answer the following questions, using complete sentences.
12. Briefly describe energy conversion by a microphone.
13. Describe the pathway that sound waves follow as they enter the ear and eventually lead to the sensation of sound.
In your textbook, read about sound qualities and beat.
For each of the statements below, write true or rewrite the italicized part to make the statement true.
The highest frequency that will resonate in a musical instrument is
called the fundamental.
15.
In a closed-pipe instrument, such as a clarinet, the harmonics are
odd-number multiples of the fundamental frequency.
16.
A sound spectrum of an instrument is a graph of wave amplitude
versus speed.
17.
Sounds perceived as consonant in most Western cultures tend to
have frequencies that are in small, whole-number ratios.
18.
Interference between two nearly identical frequencies causes
a consonance.
19.
A beat is an oscillation of wave amplitude.
20.
The frequency of the beat equals the magnitude of difference
between the frequencies of the two waves.
In your textbook, read about musical intervals.
Write the frequency ratio for the pitches in each musical interval.
21. octave
22. fifth
23. major third
24. fourth
90
Study Guide
Physics: Principles and Problems
Copyright © by Glencoe/McGraw-Hill
14.