chp16 Part2
chp16 Part2
chp16 Part2
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QuickCheck 16.8
An open-open tube of air has length
L. Which graph shows the m = 3
standing wave in this tube?
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QuickCheck 16.8
An open-open tube of air has length
L. Which graph shows the m = 3
standing wave in this tube?
A.
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QuickCheck 16.9
An open-closed tube of air of length L
has the closed end on the right. Which
graph shows the m = 3 standing wave
in this tube?
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QuickCheck 16.9
An open-closed tube of air of length L
has the closed end on the right. Which
graph shows the m = 3 standing wave
in this tube?
C.
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QuickCheck 16.10
The following tubes all support sound waves at their
fundamental frequency. Which tube has the lowest
fundamental frequency?
Slide 16-14
QuickCheck 16.10
The following tubes all support sound waves at their
fundamental frequency. Which tube has the lowest
fundamental frequency?
C.
2015 Pearson Education, Inc.
Slide 16-15
QuickCheck 16.11
Which of the following changes will increase the frequency
of the lowest-frequency standing sound wave in an openopen tube? Choose all that apply.
A.
B.
C.
D.
Slide 16-16
QuickCheck 16.11
Which of the following changes will increase the frequency
of the lowest-frequency standing sound wave in an openopen tube? Choose all that apply.
A.
B.
C.
D.
Slide 16-17
QuickCheck 16.12
At room temperature, the fundamental frequency of an
open-open tube is 500 Hz. If taken outside on a cold winter
day, the fundamental frequency will be
A. Less than 500 Hz
B. 500 Hz
C. More than 500 Hz
Slide 16-18
QuickCheck 16.12
At room temperature, the fundamental frequency of an
open-open tube is 500 Hz. If taken outside on a cold winter
day, the fundamental frequency will be
A. Less than 500 Hz
B. 500 Hz
C. More than 500 Hz
Slide 16-19
Text: p. 511
Slide 16-20
Text: p. 512
2015 Pearson Education, Inc.
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Wind Instruments
Wind instruments use holes to
change the effective length of
the tube. The first hole open
becomes a node because the
tube is open to atmosphere at
that point.
Instruments with buzzers at the end or that use vibrations
of the musicians lips generate a continuous range of
frequencies. The ones that match the resonances produce
the musical notes.
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QuickCheck 16.13
Two speakers are emitting identical sound waves with a
wavelength of 4.0 m. The speakers are 8.0 m apart and directed
toward each other, as in the following diagram.
Slide 16-32
QuickCheck 16.13
Two speakers are emitting identical sound waves with a
wavelength of 4.0 m. The speakers are 8.0 m apart and directed
toward each other, as in the following diagram.
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QuickCheck 16.14
Two loudspeakers emit sound waves
with the same wavelength and the
same amplitude. The waves are shown
displaced, for clarity, but assume that
both are traveling along the same axis. At the point where the
dot is,
A. The interference is constructive.
B. The interference is destructive.
C. The interference is somewhere between constructive and
destructive.
D. Theres not enough information to tell about the interference.
2015 Pearson Education, Inc.
Slide 16-37
QuickCheck 16.14
Two loudspeakers emit sound waves
with the same wavelength and the
same amplitude. The waves are shown
displaced, for clarity, but assume that
both are traveling along the same axis. At the point where the
dot is,
A. The interference is constructive.
B. The interference is destructive.
C. The interference is somewhere between constructive and
destructive.
D. Theres not enough information to tell about the interference.
2015 Pearson Education, Inc.
Slide 16-38
QuickCheck 16.15
Two loudspeakers emit sound waves
with the same wavelength and the same
amplitude. Which of the following
would cause there to be destructive interference at the
position of the dot?
A.
B.
C.
D.
E.
Slide 16-39
QuickCheck 16.15
Two loudspeakers emit sound waves
with the same wavelength and the same
amplitude. Which of the following
would cause there to be destructive interference at the
position of the dot?
A.
B.
C.
D.
E.
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QuickCheck 16.16
Two in-phase sources emit sound
waves of equal wavelength and
intensity. At the position of the dot,
A. The interference is
constructive.
B. The interference is destructive.
C. The interference is somewhere between constructive and
destructive.
D. Theres not enough information to tell about the
interference.
2015 Pearson Education, Inc.
Slide 16-53
QuickCheck 16.16
Two in-phase sources emit sound
waves of equal wavelength and
intensity. At the position of the dot,
A. The interference is
constructive.
B. The interference is destructive.
C. The interference is somewhere between constructive and
destructive.
D. Theres not enough information to tell about the
interference.
2015 Pearson Education, Inc.
Slide 16-54
QuickCheck 16.17
Two speakers emit sounds of nearly equal frequency, as
shown. At a point between the two speakers, the sound
varies from loud to soft. How much time elapses between
two successive loud moments?
A.
B.
C.
D.
0.5 s
1.0 s
2.0 s
4.0 s
Slide 16-55
QuickCheck 16.17
Two speakers emit sounds of nearly equal frequency, as
shown. At a point between the two speakers, the sound
varies from loud to soft. How much time elapses between
two successive loud moments?
A.
B.
C.
D.
0.5 s
1.0 s
2.0 s
4.0 s
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Text: p. 519
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Example Problem
Two speakers emit identical sinusoidal waves. The speakers
are placed 4.0 m apart. A listener moving along a line in
front of the two speakers finds loud and quiet spots as
shown in the following figure. The grid lines are spaced at
1.0 m. What is the frequency of the sound from the two
speakers?
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Beats
The superposition of two waves with slightly different
frequencies can create a wave whose amplitude shows a
periodic variation.
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Beats
The ear hears a single tone that is modulated. The
distinctive sound pattern is called beats.
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Beats
The air oscillates against your
eardrum at frequency
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QuickCheck 16.18
You hear 2 beats per second when two sound sources, both
at rest, play simultaneously. The beats disappear if source
2 moves toward you while source 1 remains at rest. The
frequency of source 1 is 500 Hz. The frequency of source
2 is
A.
B.
C.
D.
E.
496 Hz
498 Hz
500 Hz
502 Hz
504 Hz
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QuickCheck 16.18
You hear 2 beats per second when two sound sources, both
at rest, play simultaneously. The beats disappear if source
2 moves toward you while source 1 remains at rest. The
frequency of source 1 is 500 Hz. The frequency of source
2 is
A.
B.
C.
D.
E.
496 Hz
498 Hz
500 Hz
502 Hz
504 Hz
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Example Problem
A typical police radar sends out microwaves at 10.5 GHz.
The unit combines the wave reflected from a car with the
original signal and determines the beat frequency. This
beat frequency is converted into a speed. If a car is
moving at 20 m/s toward the detector, what will be the
measured beat frequency?
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