Question 1

Both particles and waves transfer energy from one location to another. Which of the following statements is true?

Accepted Answer

A)  Both methods of energy transfer follow the conservation of energy principle. 
B)  Energy transfer by particles follows the conservation of energy principle but waves do not. 
C)  Energy transfer by waves follows the conservation of energy principle but particles do not. 
D)  Whether the transfer of energy by a wave follows the conservation of energy principle depends on the speed of the wave. 
E)  Whether the transfer of energy by a particle follows the conservation of energy principle depends on the speed of the particle. 
A)  Both methods of energy transfer follow the conservation of energy principle. 
B)  Energy transfer by particles follows the conservation of energy principle but waves do not. 
C)  Energy transfer by waves follows the conservation of energy principle but particles do not. 
D)  Whether the transfer of energy by a wave follows the conservation of energy principle depends on the speed of the wave. 
E)  Whether the transfer of energy by a particle follows the conservation of energy principle depends on the speed of the particle.

Question 2

The human ear can be sensitive to sound frequencies up to 20 kHz. What wavelength does this correspond to at normal temperature and pressure?

Accepted Answer

A)  0.165 m 
B)  165 cm 
C)  16.5 mm 
D)  1650 $\times$ 10-4 m 
E)  1.65 mm 
A)  0.165 m 
B)  165 cm 
C)  16.5 mm 
D)  1650 $\times$ 10-4 m 
E)  1.65 mm

Question 3

An observer is standing on the platform of a railway station. A train goes through the station without stopping. If the frequency of the train whistle decreases by a factor of 1.2 as it approaches and then passes him, calculate the speed of the train (assume the speed of sound in air = 343 m/s).

Accepted Answer

A)  112 km/hr 
B)  31.2 km/hr 
C)  56.0 km/hr 
D)  62.0 km/hr 
E)  122 km/hr 
A)  112 km/hr 
B)  31.2 km/hr 
C)  56.0 km/hr 
D)  62.0 km/hr 
E)  122 km/hr

Question 4

The power transmitted by any harmonic wave varies directly as

Accepted Answer

A)  the period. 
B)  the square root of the frequency. 
C)  the amplitude. 
D)  the amplitude squared. 
E)  None of these is correct. 
A)  the period. 
B)  the square root of the frequency. 
C)  the amplitude. 
D)  the amplitude squared. 
E)  None of these is correct.

Question 5

If a sound of intensity I = 1.0 $\times$ 10-6 W/m2 falls on a detector of area A = 7.0 $\times$ 10-5 m2 (about the size of your eardrum), how much power is received by the detector?

Accepted Answer

A)  6.2 $\times$ 10-14 W 
B)  1.0 $\times$ 10-6 W 
C)  7.0 $\times$ 10-11 W 
D)  1.4 $\times$ 10-2 W 
E)  70 W 
A)  6.2 $\times$ 10-14 W 
B)  1.0 $\times$ 10-6 W 
C)  7.0 $\times$ 10-11 W 
D)  1.4 $\times$ 10-2 W 
E)  70 W

Question 6

You are in a park when you spot your friend 100 m away. At what lowest decibel should you shout your greetings so that your friend can just hear you? Assume that your friend has normal hearing.

Accepted Answer

A)  30 dB 
B)  40 dB 
C)  50 dB 
D)  60dB 
E)  70 dB 
A)  30 dB 
B)  40 dB 
C)  50 dB 
D)  60dB 
E)  70 dB

Question 7

The equation of a traveling wave is
Y(x, t) = 0.02 cos(0.25x - 500t)
Where the units are SI. The velocity of the wave is

Accepted Answer

A)  4.0 m/s 
B)  10 m/s 
C)  0.13 km/s 
D)  0.50 km/s 
E)  2.0 km/s 
A)  4.0 m/s 
B)  10 m/s 
C)  0.13 km/s 
D)  0.50 km/s 
E)  2.0 km/s

Question 8

A police car siren emits a sound at 600 Hz. If observer A moves toward the source at 50 km/hr, and the police car is traveling toward observer A at 100 km/hr (all speeds relative to the road), calculate the siren frequency heard by the observer A (assume the speed of sound in air = 343 m/s).

Accepted Answer

A)  626 Hz 
B)  600 Hz 
C)  679 Hz 
D)  577 Hz 
E)  970 Hz 
A)  626 Hz 
B)  600 Hz 
C)  679 Hz 
D)  577 Hz 
E)  970 Hz

Question 9

The sound level of a dog's bark is 50 dB. The intensity of a rock concert is 10,000 times that of the dog's bark. What is the sound level of the rock concert?

Accepted Answer

A)  10,050 dB 
B)  500,000 dB 
C)  90 dB 
D)  2000 dB 
E)  54 dB 
A)  10,050 dB 
B)  500,000 dB 
C)  90 dB 
D)  2000 dB 
E)  54 dB

Question 10

Two sounds differ by 30 dB. The intensity of the louder sound IL, compared with the softer IS, is IL/IS. The value of the ratio is

Accepted Answer

A)  1000 
B)  30 
C)  9 
D)  100 
E)  300 
A)  1000 
B)  30 
C)  9 
D)  100 
E)  300

Question 11

Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air,

Accepted Answer

A)  the frequency remains the same but the wavelength is shorter. 
B)  the frequency is higher but the wavelength stays the same. 
C)  the frequency is lower but the wavelength is longer. 
D)  the frequency is lower and the wavelength is shorter. 
E)  both the frequency and the wavelength remain the same. 
A)  the frequency remains the same but the wavelength is shorter. 
B)  the frequency is higher but the wavelength stays the same. 
C)  the frequency is lower but the wavelength is longer. 
D)  the frequency is lower and the wavelength is shorter. 
E)  both the frequency and the wavelength remain the same.

Question 12

A pulse moves in a string toward a free end (a ring on a post) as indicated in the sketch. On reflection, the pulse would most nearly be represented by

Accepted Answer

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

Question 13

Workmen are digging up the road using pneumatic tools. If a single tool creates a noise level of 88 decibels a few meters away, calculate the noise level if four such tools were in operation the same distance away.

Accepted Answer

A)  176 dB 
B)  90 dB 
C)  352 dB 
D)  94 dB 
E)  92 dB 
A)  176 dB 
B)  90 dB 
C)  352 dB 
D)  94 dB 
E)  92 dB

Question 14

If you were to double the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

Accepted Answer

A)  double. 
B)  quadruple. 
C)  be reduced 50%. 
D)  be reduced to 25% of its previous value. 
E)  be unchanged. 
A)  double. 
B)  quadruple. 
C)  be reduced 50%. 
D)  be reduced to 25% of its previous value. 
E)  be unchanged.

Question 15

Use the following scenario to answer the next question. A rope of length L and linear mass density $\mu$ is tied to the ceiling on one end. The other end is tied to a spring with spring constant k, and the spring is then attached to the floor, extending it by A.
-The tension of the rope at height y from the spring is

Accepted Answer

A)  kA 
B)  $\mu$gy 
C)  $\mu$gy + kA 
D)  $\mu$gy - kA 
E)  kA - $\mu$gy 
A)  kA 
B)  $\mu$gy 
C)  $\mu$gy + kA 
D)  $\mu$gy - kA 
E)  kA - $\mu$gy

Question 16

A jet engine emits a whine of frequency 3000 Hz. When the engine is moving directly away from an observer at half the speed of sound, an observer hears a frequency of

Accepted Answer

A)  1000 Hz 
B)  1500 Hz 
C)  2000 Hz 
D)  4500 Hz 
E)  6000 Hz 
A)  1000 Hz 
B)  1500 Hz 
C)  2000 Hz 
D)  4500 Hz 
E)  6000 Hz

Question 17

Which curve best illustrates 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 18

A string under tension carries a transverse wave traveling at speed v. If the tension in the string is halved and the linear density of the string is quadrupled, what is the wave speed?

Accepted Answer

A)  The wave speed is unchanged. 
B)  The wave speed is halved. 
C)  The wave speed is quadrupled. 
D)  The wave speed decreases to about 71% of v. 
E)  The wave speed increases by about 41%. 
A)  The wave speed is unchanged. 
B)  The wave speed is halved. 
C)  The wave speed is quadrupled. 
D)  The wave speed decreases to about 71% of v. 
E)  The wave speed increases by about 41%.

Question 19

To double the rate at which energy is transmitted along a string, you could

Accepted Answer

A)  double the angular frequency of the source. 
B)  double the amplitude of the wave. 
C)  double the tension in the string. 
D)  quadruple the tension in the string. 
E)  halve the linear density of the string. 
A)  double the angular frequency of the source. 
B)  double the amplitude of the wave. 
C)  double the tension in the string. 
D)  quadruple the tension in the string. 
E)  halve the linear density of the string.

Question 20

Two sounds differ by 20 dB. This means that the louder sound is _____ times as intense and _____ times as loud.

Accepted Answer

A)  twenty; twenty 
B)  one hundred; twenty 
C)  twenty; four 
D)  one hundred; four 
E)  two; two 
A)  twenty; twenty 
B)  one hundred; twenty 
C)  twenty; four 
D)  one hundred; four 
E)  two; two

Both particles and waves transfer energy from one location to another. Which of the following statements is true?

The human ear can be sensitive to sound frequencies up to 20 kHz. What wavelength does this correspond to at normal temperature and pressure?

An observer is standing on the platform of a railway station. A train goes through the station without stopping. If the frequency of the train whistle decreases by a factor of 1.2 as it approaches and then passes him, calculate the speed of the train (assume the speed of sound in air = 343 m/s).

The power transmitted by any harmonic wave varies directly as

If a sound of intensity I = 1.0 $\times$ 10^-6 W/m² falls on a detector of area A = 7.0 $\times$ 10^-5 m² (about the size of your eardrum), how much power is received by the detector?

You are in a park when you spot your friend 100 m away. At what lowest decibel should you shout your greetings so that your friend can just hear you? Assume that your friend has normal hearing.

The equation of a traveling wave is Y(x, t) = 0.02 cos(0.25x - 500t) Where the units are SI. The velocity of the wave is

A police car siren emits a sound at 600 Hz. If observer A moves toward the source at 50 km/hr, and the police car is traveling toward observer A at 100 km/hr (all speeds relative to the road), calculate the siren frequency heard by the observer A (assume the speed of sound in air = 343 m/s).

The sound level of a dog's bark is 50 dB. The intensity of a rock concert is 10,000 times that of the dog's bark. What is the sound level of the rock concert?

Two sounds differ by 30 dB. The intensity of the louder sound I_L, compared with the softer I_S, is I_L/I_S. The value of the ratio is

Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air,

A pulse moves in a string toward a free end (a ring on a post) as indicated in the sketch. On reflection, the pulse would most nearly be represented by

Workmen are digging up the road using pneumatic tools. If a single tool creates a noise level of 88 decibels a few meters away, calculate the noise level if four such tools were in operation the same distance away.

If you were to double the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

A jet engine emits a whine of frequency 3000 Hz. When the engine is moving directly away from an observer at half the speed of sound, an observer hears a frequency of

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

A string under tension carries a transverse wave traveling at speed v. If the tension in the string is halved and the linear density of the string is quadrupled, what is the wave speed?

To double the rate at which energy is transmitted along a string, you could

Two sounds differ by 20 dB. This means that the louder sound is _ times as intense and _ times as loud.

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

Both particles and waves transfer energy from one location to another. Which of the following statements is true?

The human ear can be sensitive to sound frequencies up to 20 kHz. What wavelength does this correspond to at normal temperature and pressure?

An observer is standing on the platform of a railway station. A train goes through the station without stopping. If the frequency of the train whistle decreases by a factor of 1.2 as it approaches and then passes him, calculate the speed of the train (assume the speed of sound in air = 343 m/s).

The power transmitted by any harmonic wave varies directly as

If a sound of intensity I = 1.0 ×\times× 10-6 W/m2 falls on a detector of area A = 7.0 ×\times× 10-5 m2 (about the size of your eardrum), how much power is received by the detector?

You are in a park when you spot your friend 100 m away. At what lowest decibel should you shout your greetings so that your friend can just hear you? Assume that your friend has normal hearing.

The equation of a traveling wave is Y(x, t) = 0.02 cos(0.25x - 500t) Where the units are SI. The velocity of the wave is

A police car siren emits a sound at 600 Hz. If observer A moves toward the source at 50 km/hr, and the police car is traveling toward observer A at 100 km/hr (all speeds relative to the road), calculate the siren frequency heard by the observer A (assume the speed of sound in air = 343 m/s).

The sound level of a dog's bark is 50 dB. The intensity of a rock concert is 10,000 times that of the dog's bark. What is the sound level of the rock concert?

Two sounds differ by 30 dB. The intensity of the louder sound IL, compared with the softer IS, is IL/IS. The value of the ratio is

Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. In the air,

A pulse moves in a string toward a free end (a ring on a post) as indicated in the sketch. On reflection, the pulse would most nearly be represented by

Workmen are digging up the road using pneumatic tools. If a single tool creates a noise level of 88 decibels a few meters away, calculate the noise level if four such tools were in operation the same distance away.

If you were to double the speed of a wave on a string while keeping the frequency and amplitude of the wave constant, the rate at which energy is delivered by the wave would

A jet engine emits a whine of frequency 3000 Hz. When the engine is moving directly away from an observer at half the speed of sound, an observer hears a frequency of

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

A string under tension carries a transverse wave traveling at speed v. If the tension in the string is halved and the linear density of the string is quadrupled, what is the wave speed?

To double the rate at which energy is transmitted along a string, you could

Two sounds differ by 20 dB. This means that the louder sound is _____ times as intense and _____ times as loud.

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

If a sound of intensity I = 1.0 $\times$ 10^-6 W/m² falls on a detector of area A = 7.0 $\times$ 10^-5 m² (about the size of your eardrum), how much power is received by the detector?

Two sounds differ by 30 dB. The intensity of the louder sound I_L, compared with the softer I_S, is I_L/I_S. The value of the ratio is

Two sounds differ by 20 dB. This means that the louder sound is _ times as intense and _ times as loud.