Question 1

The angle of the shock wave produced by a jet traveling at Mach 2 at an altitude of
3000 m (assume the speed of sound to be 340 m/s at this altitude) is approximately

Accepted Answer

A)  30º 
B)  40º 
C)  50º 
D)  60º 
E)  80º 
A)  30º 
B)  40º 
C)  50º 
D)  60º 
E)  80º

Question 2

When the frequency of a source is doubled, the sound produced

Accepted Answer

A)  travels at half its former speed. 
B)  travels at twice its former speed. 
C)  has half its former wavelength. 
D)  has twice its former wavelength. 
E)  is greatly improved in quality. 
A)  travels at half its former speed. 
B)  travels at twice its former speed. 
C)  has half its former wavelength. 
D)  has twice its former wavelength. 
E)  is greatly improved in quality.

Question 3

A general rule for estimating the distance in kilometers between you and a lightning bolt is to count the number of seconds between the time you see the flash and the time you hear the thunder and then divide by

Accepted Answer

A)  2 
B)  3 
C)  4 
D)  5 
E)  None of these is correct. 
A)  2 
B)  3 
C)  4 
D)  5 
E)  None of these is correct.

Question 4

A triangular wave pulse as shown by the blue line can be formed by adding

Accepted Answer

A)  harmonic sine waves with different frequencies and intensities. 
B)  harmonic cosine waves with different frequencies and intensities. 
C)  a combination of harmonic sine and cosine waves with different frequencies and intensities. 
D)  either (
A) , (
B)  or (
C)  
E)  it is not possible to form triangular using harmonic waves. 
A)  harmonic sine waves with different frequencies and intensities. 
B)  harmonic cosine waves with different frequencies and intensities. 
C)  a combination of harmonic sine and cosine waves with different frequencies and intensities. 
D)  either (
A) , (
B)  or (
C)  
E)  it is not possible to form triangular using harmonic waves.

Question 5

The speed of sound in dry air at 20ºC is 343 m/s. The speed of sound in dry air at 80ºC is

Accepted Answer

A)  86.0 m/s 
B)  172 m/s 
C)  377 m/s 
D)  686 m/s 
E)  1.27 km/s 
A)  86.0 m/s 
B)  172 m/s 
C)  377 m/s 
D)  686 m/s 
E)  1.27 km/s

Question 6

Which curve best represents the variation of wave velocity with linear density in a vibrating string?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 7

A sound pulsar unit puts out short sound bursts at constant time intervals. This unit also has a receiver to listen to the time delay from an echo from any objects or walls. If the unit is positioned such that the echo time corresponds to the sound burst interval of 0.6 s, find the distance to the reflecting wall. (velocity of sound in air = 331 m/s)

Accepted Answer

A)  150 m 
B)  50.0 m 
C)  200 m 
D)  100 m 
E)  none of the above 
A)  150 m 
B)  50.0 m 
C)  200 m 
D)  100 m 
E)  none of the above

Question 8

A siren of frequency 3.20 kHz moves away from a stationary observer with a speed of 30.5 m/s. If the speed of sound is 335 m/s, the frequency heard by the observer is

Accepted Answer

A)  2.66 kHz 
B)  2.93 kHz 
C)  3.49 kHz 
D)  3.52 kHz 
E)  3.84 kHz 
A)  2.66 kHz 
B)  2.93 kHz 
C)  3.49 kHz 
D)  3.52 kHz 
E)  3.84 kHz

Question 9

The equation of a transverse wave is
Y(x, t) = 0.02 cos(10$\pi$x - 400$\pi$t)
Where the units are SI. The velocity of the wave is

Accepted Answer

A)  0.20$\pi$ m/s 
B)  8$\pi$ m/s 
C)  40 m/s 
D)  0.20 km/s 
E)  0.40$\pi$ km/s 
A)  0.20$\pi$ m/s 
B)  8$\pi$ m/s 
C)  40 m/s 
D)  0.20 km/s 
E)  0.40$\pi$ km/s

Question 10

In which of the following is the speed of sound greatest?

Accepted Answer

A)  air 
B)  water 
C)  a vacuum 
D)  wood 
E)  steel 
A)  air 
B)  water 
C)  a vacuum 
D)  wood 
E)  steel

Question 11

Waves of amplitude 1.1 cm and wavelength 40 cm move along a 12-m long string that has a mass of 70 g and is under a tension of 15 N. Calculate the velocity of the wave.

Accepted Answer

A)  51 m/s 
B)  2570 m/s 
C)  16 m/s 
D)  15 m/s 
E)  331 m/s 
A)  51 m/s 
B)  2570 m/s 
C)  16 m/s 
D)  15 m/s 
E)  331 m/s

Question 12

Suppose the wavelength of the 656.3-nm line in the hydrogen spectrum is shifted to 656.8 - nm for light from a particular star. What can you deduce for the speed of the star relative to us?

Accepted Answer

A)  914 km/s toward us 
B)  457 km/s toward us 
C)  914 km/s away from us 
D)  none of these answers 
E)  457 km/s away from us 
A)  914 km/s toward us 
B)  457 km/s toward us 
C)  914 km/s away from us 
D)  none of these answers 
E)  457 km/s away from us

Question 13

A sound source of frequency f moves with constant velocity (less than the speed of sound) through a medium that is at rest. A stationary observer hears a sound whose frequency is appreciably different from f because

Accepted Answer

A)  the equation that relates velocity of propagation, frequency, and wavelength of a sound traveling through a medium does not apply in this situation. 
B)  the sound wave travels through the medium with a velocity different from that which it would have if the source were at rest. 
C)  the frequency of the source is changed because of its motion. 
D)  the wavelength established in the medium is not the same as it would be if the source were at rest. 
E)  interference effects set up a standing-wave pattern that alters the frequency. 
A)  the equation that relates velocity of propagation, frequency, and wavelength of a sound traveling through a medium does not apply in this situation. 
B)  the sound wave travels through the medium with a velocity different from that which it would have if the source were at rest. 
C)  the frequency of the source is changed because of its motion. 
D)  the wavelength established in the medium is not the same as it would be if the source were at rest. 
E)  interference effects set up a standing-wave pattern that alters the frequency.

Question 14

A noisy workplace has a noise level of 90 dB. You want to reduce this to a more comfortable 75 dB. By what factor must the power of the noise source be reduced? (That is, what is the ratio of the new power to the old?)

Accepted Answer

A)  0.83 
B)  0.67 
C)  0.32 
D)  0.032 
E)  0.010 
A)  0.83 
B)  0.67 
C)  0.32 
D)  0.032 
E)  0.010

Question 15

The speed of sound in air at 0ºC is 331 m/s. What is the speed of sound in air at -40ºC?

Accepted Answer

A)  241 m/s 
B)  282 m/s 
C)  306 m/s 
D)  309 m/s 
E)  379 m/s 
A)  241 m/s 
B)  282 m/s 
C)  306 m/s 
D)  309 m/s 
E)  379 m/s

Question 16

Which of the following function is NOT a possible wave equation? A and c are constants. The other symbols have their usual meaning.

Accepted Answer

A)  y(x,t) = 1/(x - vt) 
B)  y(x,t) = A e-vxt/c  
C)    
D)  y(x,t) = A cos (kx) sin (ωt) 
E)  y(x,t) = A sin(kx + ωt) 
A)  y(x,t) = 1/(x - vt) 
B)  y(x,t) = A e-vxt/c  
C)    
D)  y(x,t) = A cos (kx) sin (ωt) 
E)  y(x,t) = A sin(kx + ωt)

Question 17

From the figure, you can conclude that

Accepted Answer

A)  the wave travels slower in the medium to the left of the interface than in the medium to the right of the interface. 
B)  the wave travels faster in the medium to the left of the interface than in the medium to the right of the interface. 
C)  the wave is traveling with the same speed on both sides of the interface. 
D)  the angle of incidence is equal to the angle of refraction. 
E)  total internal reflection is not possible for a wave traveling from left to right. 
A)  the wave travels slower in the medium to the left of the interface than in the medium to the right of the interface. 
B)  the wave travels faster in the medium to the left of the interface than in the medium to the right of the interface. 
C)  the wave is traveling with the same speed on both sides of the interface. 
D)  the angle of incidence is equal to the angle of refraction. 
E)  total internal reflection is not possible for a wave traveling from left to right.

Question 18

Which curve best represents the variation of wave velocity with tension in a vibrating string?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 19

At an outdoor bandstand, what would be the difference in the sound intensity level (dB) received by a listener 5 m from the bandstand and a listener 40 m from the bandstand, assuming there is no sound reflection? [$\beta$ = 10 log(I/I0)]

Accepted Answer

A)  8 dB 
B)  9 dB 
C)  10 dB 
D)  18 dB 
E)  The answer depends on how loudly the band plays. 
A)  8 dB 
B)  9 dB 
C)  10 dB 
D)  18 dB 
E)  The answer depends on how loudly the band plays.

Question 20

Which of the following statements about longitudinal and transverse pressure waves is NOT true?

Accepted Answer

A)  Longitudinal pressure waves can travel through fluids. 
B)  Transverse pressure waves can travel through fluids. 
C)  Longitudinal pressure waves can travel through solids. 
D)  Transverse pressure waves can travel through solids. 
E)  Both longitudinal and transverse pressure waves transport energy. 
A)  Longitudinal pressure waves can travel through fluids. 
B)  Transverse pressure waves can travel through fluids. 
C)  Longitudinal pressure waves can travel through solids. 
D)  Transverse pressure waves can travel through solids. 
E)  Both longitudinal and transverse pressure waves transport energy.

The angle of the shock wave produced by a jet traveling at Mach 2 at an altitude of 3000 m (assume the speed of sound to be 340 m/s at this altitude) is approximately

When the frequency of a source is doubled, the sound produced

A general rule for estimating the distance in kilometers between you and a lightning bolt is to count the number of seconds between the time you see the flash and the time you hear the thunder and then divide by

A triangular wave pulse as shown by the blue line can be formed by adding

The speed of sound in dry air at 20ºC is 343 m/s. The speed of sound in dry air at 80ºC is

Which curve best represents the variation of wave velocity with linear density in a vibrating string?

A siren of frequency 3.20 kHz moves away from a stationary observer with a speed of 30.5 m/s. If the speed of sound is 335 m/s, the frequency heard by the observer is

The equation of a transverse wave is Y(x, t) = 0.02 cos(10 $\pi$ x - 400 $\pi$ t) Where the units are SI. The velocity of the wave is

In which of the following is the speed of sound greatest?

Waves of amplitude 1.1 cm and wavelength 40 cm move along a 12-m long string that has a mass of 70 g and is under a tension of 15 N. Calculate the velocity of the wave.

Suppose the wavelength of the 656.3-nm line in the hydrogen spectrum is shifted to 656.8 - nm for light from a particular star. What can you deduce for the speed of the star relative to us?

A sound source of frequency f moves with constant velocity (less than the speed of sound) through a medium that is at rest. A stationary observer hears a sound whose frequency is appreciably different from f because

A noisy workplace has a noise level of 90 dB. You want to reduce this to a more comfortable 75 dB. By what factor must the power of the noise source be reduced? (That is, what is the ratio of the new power to the old?)

The speed of sound in air at 0ºC is 331 m/s. What is the speed of sound in air at -40ºC?

Which of the following function is NOT a possible wave equation? A and c are constants. The other symbols have their usual meaning.

From the figure, you can conclude that

Which curve best represents the variation of wave velocity with tension in a vibrating string?

At an outdoor bandstand, what would be the difference in the sound intensity level (dB) received by a listener 5 m from the bandstand and a listener 40 m from the bandstand, assuming there is no sound reflection? [ $\beta$ = 10 log(I/I₀)]

Which of the following statements about longitudinal and transverse pressure waves is NOT true?

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

Filters

Exam 15: Wave Motion

The angle of the shock wave produced by a jet traveling at Mach 2 at an altitude of 3000 m (assume the speed of sound to be 340 m/s at this altitude) is approximately

When the frequency of a source is doubled, the sound produced

A general rule for estimating the distance in kilometers between you and a lightning bolt is to count the number of seconds between the time you see the flash and the time you hear the thunder and then divide by

A triangular wave pulse as shown by the blue line can be formed by adding

The speed of sound in dry air at 20ºC is 343 m/s. The speed of sound in dry air at 80ºC is

Which curve best represents the variation of wave velocity with linear density in a vibrating string?

A siren of frequency 3.20 kHz moves away from a stationary observer with a speed of 30.5 m/s. If the speed of sound is 335 m/s, the frequency heard by the observer is

The equation of a transverse wave is Y(x, t) = 0.02 cos(10 π\piπ x - 400 π\piπ t) Where the units are SI. The velocity of the wave is

In which of the following is the speed of sound greatest?

Waves of amplitude 1.1 cm and wavelength 40 cm move along a 12-m long string that has a mass of 70 g and is under a tension of 15 N. Calculate the velocity of the wave.

Suppose the wavelength of the 656.3-nm line in the hydrogen spectrum is shifted to 656.8 - nm for light from a particular star. What can you deduce for the speed of the star relative to us?

A sound source of frequency f moves with constant velocity (less than the speed of sound) through a medium that is at rest. A stationary observer hears a sound whose frequency is appreciably different from f because

A noisy workplace has a noise level of 90 dB. You want to reduce this to a more comfortable 75 dB. By what factor must the power of the noise source be reduced? (That is, what is the ratio of the new power to the old?)

The speed of sound in air at 0ºC is 331 m/s. What is the speed of sound in air at -40ºC?

Which of the following function is NOT a possible wave equation? A and c are constants. The other symbols have their usual meaning.

From the figure, you can conclude that

Which curve best represents the variation of wave velocity with tension in a vibrating string?

At an outdoor bandstand, what would be the difference in the sound intensity level (dB) received by a listener 5 m from the bandstand and a listener 40 m from the bandstand, assuming there is no sound reflection? [ β\betaβ = 10 log(I/I0)]

Which of the following statements about longitudinal and transverse pressure waves is NOT true?

Systems of Measurement

Motion in One Dimension

Motion in Two and Three Dimensions

Newtons Laws

Applications of Newtons Laws

Work and Energy

Conservation of Energy

Systems of Particles and Conservation of Linear Momentum

Rotation

Conservation of Angular Momentum

Gravity

Static Equilibrium and Elasticity

Fluids

Oscillations

Superposition and Standing Waves

Temperature and the Kinetic Theory of Gases

Heat and the First Law of Thermodynamics

The Second Law of Thermodynamics

Thermal Properties and Processes

Filters

The equation of a transverse wave is Y(x, t) = 0.02 cos(10 $\pi$ x - 400 $\pi$ t) Where the units are SI. The velocity of the wave is

At an outdoor bandstand, what would be the difference in the sound intensity level (dB) received by a listener 5 m from the bandstand and a listener 40 m from the bandstand, assuming there is no sound reflection? [ $\beta$ = 10 log(I/I₀)]