# Quiz 15: Traveling Waves and Sound

Physics & Astronomy

Q 1Q 1

What is the wavelength of the wave shown in the figure?
A)8 m.
B)4 m.
C)2 m.
D)1 m.
E)It cannot be determined from the given information.

Free

Multiple Choice

E

Q 2Q 2

What is the frequency of the wave shown in the figure?
A)0.5 Hz.
B)1 Hz.
C)2 Hz.
D)4 Hz.
E)It cannot be determined from the given information.

Free

Multiple Choice

A

Q 3Q 3

Which one of the curves shown in the figure best represents the variation of wave speed v as a function of tension for transverse waves on a stretched string?
A)A
B)B
C)C
D)D
E)E

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Multiple Choice

B

Q 4Q 4

A string of mass m is under tension, and the speed of a wave in the string is v. What will be the speed of a wave in the string if the mass of the string is increased to 2m but with no change in the length or tension?
A)v/2
B)v/
C)v
D)2v
E)4v

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Multiple Choice

Q 5Q 5

A string of length L is under tension, and the speed of a wave in the string is v. What will be the speed of a wave in the string if the length is increased to 2L but with no change in the mass or tension?
A)v/2
B)v/
C)v
D)2v
E)4v

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Multiple Choice

Q 6Q 6

When a certain string is under tension T, the speed of a wave in the string is v. What will be the speed of a wave in the string if the tension is increased to 2T without changing the mass or length of the string?
A)v/2
B)v/
C)v
D)2v
E)4v

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Multiple Choice

Q 7Q 7

Four waves are described by the following equations, where distances are measured in meters and times in seconds. I. y = 0.12 cos(3x - 21t)
II. y = 0.15 sin(6x + 42t)
III. y = 0.13 cos(6x + 21t)
IV. y = -0.23 sin(3x - 42t)
Which of these waves have the same speed?
A)I and II
B)I and III
C)II and III
D)III and IV
E)II and IV

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Multiple Choice

Q 8Q 8

Four waves are described by the following equations, where distances are measured in meters and times in seconds. I. y = 0.12 cos(3x - 21t)
II. y = 0.15 sin(6x + 42t)
III. y = 0.13 cos(6x + 21t)
IV. y = -0.23 sin(3x - 42t)
Which of these waves have the same period?
A)I and III, and also II and IV
B)I and IV, and also II and III
C)I and II, and also III and IV
D)All of them have the same period.
E)They all have different periods.

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Multiple Choice

Q 9Q 9

The intensity of the waves from a point source at a distance d from the source is I. What is the intensity at a distance 2d from the source?
A)4I
B)2I
C)I/2
D)I/4
E)I/

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Multiple Choice

Q 10Q 10

The intensity of the waves from a point source at a distance d from the source is I. At what distance from the sources is the intensity equal to 2I?
A)d/2
B)d/
C)d/4
D)d/8

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Multiple Choice

Q 11Q 11

Why does the intensity of waves from a small source decrease with the square of the distance from the source?
A)The waves run out of energy as they travel.
B)The waves spread out as they travel.
C)The medium through which the waves travel absorbs the energy of the waves.
D)The waves slow down as they travel away from the source.
E)The frequency of the waves decreases as they get farther from the source.

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Multiple Choice

Q 12Q 12

Seven seconds after a brilliant flash of lightning, thunder shakes the house. Approximately how far was the lightning strike from the house?
A)much closer than one kilometer
B)about one kilometer away
C)about two kilometers away
D)much farther away than two kilometers
E)It is impossible to say.

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Multiple Choice

Q 13Q 13

What characteristics of a sound wave are related to the "pitch" of a musical note? (There could be more than one correct choice.)
A)amplitude
B)wavelength
C)frequency
D)period

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Multiple Choice

Q 14Q 14

Sound A has a high pitch and sound B has a low pitch. Which of the following statements about these two sounds are correct? (There could be more than one correct choice.)
A)The wavelength of A is longer than the wavelength of B.
B)The period of A is shorter than the period of B.
C)The frequency of A is greater than the frequency of B.
D)Sound B travels faster than sound B through air.
E)The amplitude of A is larger than the amplitude of B.

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Multiple Choice

Q 15Q 15

You double your distance from a sound source that is radiating equally in all directions. What happens to the intensity of the sound? It reduces to
A)one-half its original value.
B)one-fourth its original value.
C)one-sixteenth its original value.
D)none of the above

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Multiple Choice

Q 16Q 16

Suppose that a sound source is emitting waves uniformly in all directions. If you move to a point twice as far away from the source, the frequency of the sound will be
A)unchanged.
B)half as great.
C)one-fourth as great.
D)twice as great.

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Multiple Choice

Q 17Q 17

As you are moving very quickly toward a speaker emitting a pure tone, which characteristics of the sound get larger? (There may be more than one correct choice.)
A)frequency
B)amplitude
C)wavelength
D)period
E)loudness

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Multiple Choice

Q 18Q 18

In many cartoon shows, a character runs off a cliff, realizes his predicament, and lets out a scream. He continues to scream as he falls. If the physical situation is portrayed correctly, from the vantage point of an observer at the top of the cliff leaning over the edge, the pitch of the scream as he falls should be
A)higher than the original pitch and constant.
B)higher than the original pitch and increasing as he falls.
C)lower than the original pitch and constant.
D)lower than the original pitch and decreasing as he falls.
E)It is impossible to predict.

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Multiple Choice

Q 19Q 19

In many cartoon shows, a character runs off a cliff, realizes his predicament, and lets out a scream. He continues to scream as he falls. If the physical situation is portrayed correctly, from the vantage point of an observer at the foot of the cliff, the pitch of the scream as he falls should be
A)higher than the original pitch and constant.
B)higher than the original pitch and increasing as he falls.
C)lower than the original pitch and constant.
D)lower than the original pitch and decreasing as he falls.
E)It is impossible to predict.

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Multiple Choice

Q 20Q 20

A fisherman fishing from a pier observes that the float on his line bobs up and down, taking 2.4 s to move from its highest point to its lowest point. He also estimates that the distance between adjacent wave crests is 48 m. What is the speed of the waves going past the pier?
A)1.0 m/s
B)20 m/s
C)10 m/s
D)5.0 m/s
E)120 m/s

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Multiple Choice

Q 21Q 21

A tsunami, an ocean wave generated by an earthquake, propagates along the open ocean at 700 km/hr and has a wavelength of 750 km. What is the frequency of the waves in such a tsunami?
A)0.93 Hz
B)0.00026 Hz
C)1.1 Hz
D)6.8 Hz
E)0.15 Hz

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Multiple Choice

Q 22Q 22

What is the frequency of a pressure wave of wavelength 2.5 m that is traveling at 1400 m/s?
A)178 Hz
B)1.78 kHz
C)560 Hz
D)5.6 kHz

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Multiple Choice

Q 23Q 23

If a wave has a speed of 362 m/s and a period of 4.17 ms, what is its wavelength?
A)1510 m
B)1.51 m
C)86.8 m
D)86,800 m
E)0.0115 m

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Multiple Choice

Q 24Q 24

The figure shows a "snapshot" of a wave at a given instant of time. The frequency of this wave is 120 Hz. What are the (a)amplitude, (b)wavelength, and (c)speed of this wave?

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Essay

Q 25Q 25

The speed of sound in steel is 5000 m/s. What is the wavelength of a sound wave of frequency in steel?
A)7.58 m
B)2.41 m
C)1.21 m
D)0.829 m
E)0.132 m

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Multiple Choice

Q 26Q 26

Crests of an ocean wave pass a pier every If the waves are moving at what is the wavelength of the ocean waves?
A)56 m
B)28 m
C)64 m
D)48 m

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Multiple Choice

Q 27Q 27

Transverse waves travel at in a string that is subjected to a tension of If the string is long, what is its mass?
A)0.515 kg
B)0.216 kg
C)0.366 kg
D)0.597 kg

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Multiple Choice

Q 28Q 28

A piano wire of linear mass density 0.0050 kg/m is under a tension of 1350 N. What is the wave speed in this wire?
A)130 m/s
B)260 m/s
C)520 m/s
D)1040 m/s

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Multiple Choice

Q 29Q 29

A wave whose wavelength is 0.500 m is traveling down a 500-m long wire whose total mass is 25 kg and is under a tension of 2000 N.
(a)What is the speed of the wave on the wire?
(b)Find the frequency of this wave.

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Essay

Q 30Q 30

The density of aluminum is 2700 kg/m

^{3}. If transverse waves travel at in an aluminum wire of diameter what is the tension on the wire? A)65 N B)39 N C)52 N D)78 NFree

Multiple Choice

Q 31Q 31

A rope with a total mass of 25.0 kg is tied to a tree on one side of a 125-m wide ravine. You are pulling on the other end of the rope with a force of 415 N. If you pluck the rope at your end, how long will it take the pulse to travel across the ravine to the tree?

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Essay

Q 32Q 32

A 2.31-kg rope is stretched between supports that are 10.4 m apart, and has a tension in it of 49.2 N. If one end of the rope is slightly tweaked, how long will it take for the resulting disturbance to reach the other end?
A)0.699 s
B)0.720 s
C)0.664 s
D)0.615 s

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Multiple Choice

Q 33Q 33

A 1.1-kg uniform bar of metal is 0.40 m long and has a diameter of 2.0 cm. When someone bangs one end of this bar, a 1.5 MHz shock wave is travels along the length of the bar and reaches the other end in 0.12 ms. What is the wavelength of the shock wave in the metal?
A)2.2 mm
B)2.6 mm
C)3.0 mm
D)3.4 mm
E)3.8 mm

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Multiple Choice

Q 34Q 34

A 10-gram wire that is 6.0 m long is under tension. When a transverse wave of frequency 280 Hz travels along the wire, its wavelength is 0.60 m,and its amplitude is 8.4 mm. How much time does it take for a crest of the transverse wave to travel the length of the wire?
A)36 ms
B)31 ms
C)40 ms
D)44 ms
E)49 ms

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Multiple Choice

Q 35Q 35

A 90-gram wire that is 1.0 m long is under tension. When a transverse wave of frequency 890 Hz travels down the wire, its wavelength is 0.10 m and its amplitude is 6.5 mm. What is the tension in the wire?
A)710 N
B)820 N
C)930 N
D)1000 N
E)1100 N

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Multiple Choice

Q 36Q 36

An earthquake generates three kinds of waves: surface waves (L-waves), which are the slowest and weakest, shear (S)waves, which are transverse waves and carry most of the energy, and pressure (P)waves, which are longitudinal waves and are the fastest. The speed of P waves is approximately 7 km/s, and that of S waves is about 4 km/s. People do not generally feel the P waves, but animals seem to be sensitive to them. If a person reports that her dog started barking 20 seconds "before the earthquake," then approximately how far was the origin of the earthquake?
A)100 km
B)200 km
C)300 km
D)400 km
E)500 km

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Multiple Choice

Q 37Q 37

A 15-m rope is pulled taut with a tension of 140 N. It takes 0.545 s for a wave to propagate along the rope. What is the mass of the rope?
A)1.7 kg
B)2.1 kg
C)2.8 kg
D)5.1 kg
E)3.2 kg

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Multiple Choice

Q 38Q 38

Two steel wires are stretched with the same tension. The first wire has a diameter of 0.610 mm and the second wire has a diameter of 0.910 mm. If the speed of waves traveling along the first wire is 54.0 m/s, what is the speed of waves traveling along the second wire?
A)24.9 m/s
B)27.2 m/s
C)36.2 m/s
D)81.0 m/s
E)100 m/s

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Multiple Choice

Q 39Q 39

A crane lifts a 2500-kg beam at a steady rate of 15 cm/s using a steel cable whose mass per unit length is 0.65 kg/m. What is the speed of transverse waves on this cable?
A)230 m/s
B)580 m/s
C)1200 m/s
D)1900 m/s
E)190 m/s

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Multiple Choice

Q 40Q 40

A crane lifts a 2500-kg beam using a steel cable whose mass per unit length is 0.650 kg/m. What is the speed of transverse waves on this cable if the upward acceleration of the beam is a steady 3.00 m/s

^{2}? A)194 m/s B)578 m/s C)1220 m/s D)1880 m/s E)222 m/sFree

Multiple Choice

Q 41Q 41

A wire that is 1.0 m long with a mass of 90 g is under a tension of 710 N. When a transverse wave travels on the wire, its wavelength is 0.10 m and its amplitude is 6.5 mm. What is the frequency of this wave?
A)890 Hz
B)920 Hz
C)1000 Hz
D)1200 Hz
E)1500 Hz

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Multiple Choice

Q 42Q 42

What is the wave speed in a brass wire with a radius of 0.500 mm stretched with a tension of 125 N? The density of brass is 8.60 × 10

^{3}kg/m^{3}. A)0.121 m/s B)100 m/s C)136 m/s D)500 m/s E)68.8 m/sFree

Multiple Choice

Q 43Q 43

The vertical displacement y(x,t)of a horizontal string aligned along the x-axis is given by the equation y(x,t)= (6.00 mm)cos[(3.25 m

^{-1})x - (7.22 s^{-1})t]. What are the (a)wavelength and (b)period of this wave?Free

Essay

Q 44Q 44

The vertical displacement y(x,t)of a horizontal string aligned along the x-axis is given by the equation y(x,t)= (6.00 mm)cos[(3.25 m

^{-1})x - (7.22 s^{-1})t]. What are the (a)speed and (b)amplitude of this wave?Free

Essay

Q 45Q 45

Find the speed of an ocean wave whose displacement is given by the equation where x and y are in meters and t is in seconds.
A)2.5 m/s
B)1.9 m/s
C)3.5 m/s
D)4.5 m/s

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Multiple Choice

Q 46Q 46

What are the wavelength (in meters)and frequency (in hertz)of a wave whose displacement is given by the equation y = 0.5 sin(0.20x + 120t), where x and y are in meters and t is in seconds?
A)10 m, 0.50 Hz
B)5.0 m, 10 Hz
C)19 m, 120 Hz
D)31 m, 19 Hz
E)0.20 m, 120 Hz

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Multiple Choice

Q 47Q 47

Light from a laser forms a 1.31-mm diameter spot on a wall. If the light intensity in the spot is what is the power output of the laser? Assume that all the light emitted by the laser hits the spot.
A)21.3 mW
B)13.2 mW
C)17.9 mW
D)24.7 mW

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Multiple Choice

Q 48Q 48

Calculate the light intensity 1.45 m from a light bulb that radiates 100 W equally in all directions.
A)3.78 W/m

^{2}B)4.36 W/m^{2}C)47.6 W/m^{2}D)54.7 W/m^{2}Free

Multiple Choice

Q 49Q 49

The average intensity of sunlight impinging on Earth is measured to be about 1.4 kW/m

^{2}. What is the power of sunlight emitted by the sun? (Earth-Sun distance = 1.5 × 10^{8}km, Earth radius = 6.4 × 10^{3}km) A)4.0 × 10^{26}W B)3.2 × 10^{22}W C)7.2 × 10^{14}W D)7.6 × 10^{8}WFree

Multiple Choice

Q 50Q 50

An elephant can hear sound with a frequency of 15 Hz. What is the wavelength of this wave if the speed of sound in air is 343 m/s?

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Essay

Q 51Q 51

You drop a stone down a well that is 9.5 m deep. How long is it before you hear the splash? The speed of sound in air is 343 m/s and air resistance is negligible.
A)1.2 s
B)1.3 s
C)1.4 s
D)1.5 s
E)1.6 s

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Multiple Choice

Q 52Q 52

The speed of sound through the ground is about 6.0 km/s while the speed of sound in air is 343 m/s. A very powerful explosion occurs some distance away and you feel the ground vibrate 60 seconds before you hear the sound of the explosion. How far away is the explosion?
A)20 km
B)22 km
C)25 km
D)27 km
E)30 km

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Multiple Choice

Q 53Q 53

Two motors in a factory are running at slightly different rates. One runs at 825.0 rpm and the other at You hear the sound intensity increase and then decrease periodically due to wave interference. How long does it take between successive instances of the sound intensity increasing?
A)1.54 s
B)1.43 s
C)1.66 s
D)1.79 s

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Multiple Choice

Q 54Q 54

A plucked guitar string produces a sound wave of frequency 0.44 kHz on a day when the speed of sound is 340 m/s.
(a)What is the wavelength of the sound wave?
(b)How much time elapses between the impacts of two adjacent compressions of the sound wave on your eardrum?

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Essay

Q 55Q 55

What is the intensity level in decibels of a sound with intensity 10

^{-3}W/m^{2}? The threshold of human hearing is 1.0 × 10^{-12}W/m^{2}. A)30 dB B)60 dB C)90 dB D)96 dBFree

Multiple Choice

Q 56Q 56

What is the intensity of a 70-dB sound? The threshold of human hearing is 1.0 × 10

^{-12}W/m^{2}. A)10^{-4}W/m^{2}B)10^{-5}W/m^{2}C)10^{-6}W/m^{2}D)10^{-7}W/m^{2}Free

Multiple Choice

Q 57Q 57

What is the ratio of the intensities of two sounds with intensity levels of 70 dB and 40 dB?
A)10:1
B)100:1
C)1000:1
D)10,000:1

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Multiple Choice

Q 58Q 58

If the intensity level by 15 identical engines in a garage is 100 dB, what is the intensity level generated by each one of these engines?
A)67 dB
B)13 dB
C)44 dB
D)88 dB

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Multiple Choice

Q 59Q 59

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10

^{-10}W/m^{2}. What is the power emitted by the source? A)2.1 × 10^{-8}W B)2.7 × 10^{-7}W C)2.1 × 10^{-6}W D)2.7 × 10^{-5}WFree

Multiple Choice

Q 60Q 60

The intensity at a distance of 6.0 m from a source that is radiating equally in all directions is 6.0 × 10

^{-10}W/m^{2}. What is the intensity level in dB? The threshold of human hearing is 1.0 × 10^{-12}W/m^{2}. A)18 dB B)23 dB C)28 dB D)32 dBFree

Multiple Choice

Q 61Q 61

A barking dog delivers about 1.0 mW of power, which is assumed to be uniformly distributed in all directions. What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10

^{-12}W/m^{2}. A)61 dB B)63 dB C)65 dB D)68 dBFree

Multiple Choice

Q 62Q 62

The intensity level is 65 dB at a distance 5.00 m from a barking dog. What would be a reasonable estimate for the intensity level if two identical dogs very close to each other were barking? You can ignore any interference effects.
A)65 dB
B)68 dB
C)130 dB
D)136 dB

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Multiple Choice

Q 63Q 63

At a distance of 15.0 m from a sound source, the intensity level is 60.0 dB. What is the intensity level (in decibels)at a point 2.00 m from the source if the source radiates equally in all directions?
A)55.7 dB
B)57.5 dB
C)75.5 dB
D)77.5 dB

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Multiple Choice

Q 64Q 64

The sound intensity level 5.0 m from a point source is 95 dB. At what distance will it be 75 dB?
A)25 m
B)50 m
C)75 m
D)225 m

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Multiple Choice

Q 65Q 65

A certain siren radiates sound uniformly in all directions. At a distance of 17 m from the siren, the intensity level is 49 db. How many watts of power does this siren put out? The threshold of human hearing is 1.0 × 10

^{-12}W/m^{2}.Free

Essay

Q 66Q 66

You double your distance from a sound source that is radiating equally in all directions. What happens to the intensity level of the sound? It drops by
A)2 dB.
B)3 dB.
C)6 dB.
D)8 dB.

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Multiple Choice

Q 67Q 67

By how many decibels does the intensity level of a sound decrease when you triple your distance from a source of sound?
A)9.5 dB
B)4.8 dB
C)6.0 dB
D)12 dB
E)3.0 dB

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Multiple Choice

Q 68Q 68

A certain factory whistle can be heard up to a distance of 2.5 km. Assuming that the acoustic output of the whistle is uniform in all directions, how much acoustic power is emitted by the whistle? The threshold of human hearing is 1.0 × 10

^{-12}W/m^{2}. A)0.079 mW B)0.026 mW C)0.26 mW D)0.79 mW E)2.6 mWFree

Multiple Choice

Q 69Q 69

A certain factory whistle can be heard up to a distance of 9.8 km. Assuming that the acoustic output of the whistle is uniform in all directions, at what distance from the factory is the intensity level of the whistle sound equal to 25 dB? The threshold of human hearing is 1.0 × 10

^{-12}W/m^{2}. A)550 m B)660 m C)830 m D)940 m E)1100 mFree

Multiple Choice

Q 70Q 70

By how many decibels does the intensity level of a sound increase when you triple the intensity of a source of sound?
A)9.5 dB
B)4.8 dB
C)6.0 dB
D)3.0 dB
E)12 dB

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Multiple Choice

Q 71Q 71

A sound of 40 decibels is
A)twice as intense as a sound of 20 decibels.
B)four times as intense as a sound of 20 decibels.
C)10 times as intense as a sound of 20 decibels.
D)100 times as intense as a sound of 20 decibels.
E)1000 times as intense as a sound of 20 decibels.

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Multiple Choice

Q 72Q 72

A long-term exposure to the sound of a riveting machine can cause your threshold of hearing to shift from 0 dB to 30 dB. What is the sound intensity of a 30-dB sound? The normal lowest detectable intensity is 1.0 × 10

^{-12}W/m^{2}.Free

Essay

Q 73Q 73

A certain glass window reduces the intensity level of the sound from 72 dB to 47 dB. By what factor is the acoustic power reduced by this glass window?
A)3.2 × 10

^{-3}B)2.2 × 10^{-2}C)5.6 × 10^{-2}D)1.0 × 10^{-1}E)1.5 × 10^{-1}Free

Multiple Choice

Q 74Q 74

Two people are talking at a distance of 3.0 m from where you are, and you measure the sound intensity as 1.1 × 10

^{-7}W/m^{2}. Another student is 4.0 m away from the talkers. Calculate a reasonable estimate for the sound intensity that the other student measures. A)6.2 × 10^{-8}W/m^{2}B)1.5 × 10^{-7}W/m^{2}C)8.3 × 10^{-8}W/m^{2}D)7.8 × 10^{-7}W/m^{2}E)2.5 × 10^{-8}W/m^{2}Free

Multiple Choice

Q 75Q 75

A crying baby emits sound with an intensity of 8.0 × 10

^{-8}W/m^{2}. Calculate a reasonable estimate for the intensity level from a set of quintuplets (five babies), all crying simultaneously at the same place? The lowest detectable intensity is 1.0 × 10^{-12}W/m^{2}. A)79 dB B)69 dB C)56 dB D)49 dB E)36 dBFree

Multiple Choice

Q 76Q 76

If the intensity level of one trombone is 70 dB, calculate a reasonable estimate for the intensity level of 76 trombones all playing simultaneously in the same place?
A)146 dB
B)89 dB
C)70 dB
D)76 dB
E)82 dB

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Multiple Choice

Q 77Q 77

As shown in the figure, a man is traveling on a bicycle along a straight road that runs parallel to and right next to some railroad tracks. While moving at 10 m/s, he hears the whistle of a train that is behind him, as shown in the figure. The frequency emitted by the train's whistle is but the frequency the man hears is The speed of sound is 340 m/s.
(a)What frequency is heard by a stationary observer located between the train and the bicycle?
(b)What is the speed of the train, and is the train traveling away from or toward the bicycle?

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Essay

Q 78Q 78

A factory siren indicating the end of a shift has a frequency of 80 Hz where the speed of sound in air is 343 m/s. What frequency is perceived by the occupant of a car that is traveling at 30 m/s (a)towards the factory and (b)away from the factory?

Free

Essay

Q 79Q 79

A car approaches you at a constant speed, sounding its horn, and you hear a frequency of 76 Hz. After the car goes by, you hear a frequency of 65 Hz. What is the frequency of the sound emitted by the horn? The speed of sound in the air is 343 m/s.
A)68 Hz
B)69 Hz
C)70 Hz
D)71 Hz
E)72 Hz

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Multiple Choice

Q 80Q 80

As you stand by the side of the road, a car approaches you at a constant speed, sounding its horn, and you hear a frequency of 76 Hz. After the car goes by, you hear a frequency of 65 Hz. What is the speed of the car? The speed of sound in the air is 343 m/s.
A)26 m/s
B)27 m/s
C)28 m/s
D)29 m/s
E)30 m/s

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Multiple Choice

Q 81Q 81

You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind at constant speed and you perceive the frequency as . You are relieved that he is in pursuit of a different driver when he continues past you, but now you perceive the frequency as What is the speed of the police car? The speed of sound in air is
A)38.4 m/s
B)30 m/s
C)39.2 m/s
D)40.1 m/s
E)41.7 m/s

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Multiple Choice

Q 82Q 82

You are driving along a highway at 35.0 m/s when you hear the siren of a police car approaching you from behind at constant speed and you perceive the frequency as 1310 Hz. You are relieved that he is in pursuit of a different driver when he continues past you, but now you perceive the frequency as 1240 Hz. What is the frequency of the siren in the police car? The speed of sound in air is 343 m/s.
A)1300 Hz
B)1320 Hz
C)1270 Hz
D)1360 Hz
E)1370 Hz

Free

Multiple Choice

Q 83Q 83

You are driving along a highway at 25 m/s when you hear the siren of an emergency vehicle traveling at constant speed in the opposite direction on the other side of the highway. When the vehicle is approaching you, you hear the frequency of the siren as 2380 Hz, but when it is past you the frequency becomes 1680 Hz. What is the speed of the vehicle? The speed of sound in air is 343 m/s.
A)35 m/s
B)32 m/s
C)30 m/s
D)41 m/s
E)50 m/s

Free

Multiple Choice

Q 84Q 84

You are driving along a highway at 25.0 m/s when you hear the siren of an emergency vehicle traveling at constant speed in the opposite direction on the other side of the highway. When the vehicle is approaching you, you hear the frequency of the siren as 2380 Hz, but when it is past you the frequency becomes 1680 Hz. What is the frequency of the siren? The speed of sound in air is 343 m/s.
A)1850 Hz
B)2000 Hz
C)2050 Hz
D)2010 Hz
E)1980 Hz

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Multiple Choice

Q 85Q 85

A whistle produces sound of frequency of 1.00 kHz. If a listener moves with a speed of 30 m/s away from the whistle, what frequency does this person hear if the sound speed is 340 m/s?
A)912 Hz
B)919 Hz
C)1000 Hz
D)1090 Hz

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Multiple Choice

Q 86Q 86

A police car has an 800-Hz siren. It is traveling at 35.0 m/s on a day when the speed of sound through air is 340 m/s. The car approaches and passes an observer who is standing along the roadside. What change of frequency does the observer hear?
A)0 Hz
B)82 HZ
C)166 Hz
D)249 Hz

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Multiple Choice

Q 87Q 87

What is the frequency does a stationary observer hear when a train approaches her with a speed of 30 m/s. The frequency of the train horn is 0.600 kHz and the speed of sound is 340 m/s.
A)551 Hz
B)600 Hz
C)653 Hz
D)658 Hz

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Multiple Choice

Q 88Q 88

You are moving at 120 km/h toward a stationary train. The train blows its 0.400-kHz whistle. Take the speed of sound to be 340 m/s. What frequency do you hear?
A)444 Hz
B)439 Hz
C)364 Hz
D)361 Hz

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Multiple Choice

Q 89Q 89

A train is traveling away from you at 120 km/h. It blows its whistle, and you hear a tone of 0.400 kHz. Take the speed of sound to be 340 m/s. What frequency does the whistle actually produce?
A)444 Hz
B)439 Hz
C)364 Hz
D)361 Hz

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Multiple Choice

Q 90Q 90

Sonar is used to determine the speed of an object. A 40.0-kHz signal is sent out, and a 42.0-kHz signal is returned. If the speed of sound is 345 m/s, how fast is the object moving?
A)6.9 m/s
B)8.4 m/s
C)331 m/s
D)347 m/s

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Multiple Choice

Q 91Q 91

A bat emits a sound at a frequency of 39.0 kHz as it approaches a wall. The bat detects beats with a frequency of 827 Hz between the sound it emits and the echo bouncing from the wall. What is the speed of the bat if the speed of sound in air is 343 m/s?
A)2.7 m/s
B)3.0 m/s
C)3.6 m/s
D)5.4 m/s
E)9.0 m/s

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Multiple Choice

Q 92Q 92

Two in-phase loudspeakers are some distance apart. They emit sound with a frequency of 536 Hz. A microphone is moved between the speakers along the line joining the two speakers with a constant speed of 1.60 m/s. What beat frequency is observed? The speed of sound in air is 343 m/s.
A)5.00 Hz
B)6.00 Hz
C)7.00 Hz
D)8.00 Hz
E)9.00 Hz

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Multiple Choice

Q 93Q 93

A siren emitting sound of frequency 1000 Hz approaches a stationary observer at one-half the speed of sound. The observer hears a frequency of
A)1000 Hz
B)2000 Hz.
C)500 Hz.
D)1500 Hz.
E)none of the above.

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Multiple Choice

Q 94Q 94

The sound from the whistle of a truck moving at 17.0 m/s toward a cliff reflects from the cliff and is heard by the driver of the truck. When it is parked at the side of the road, the whistle from the truck produces sound of frequency 2.267 kHz. As observed by the driver of the truck, what is the change in frequency the sound from the whistle due to the reflection? The speed of sound is 343 m/s.
A)236 Hz
B)228 Hz
C)207 Hz
D)118 Hz
E)472 Hz

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Multiple Choice