Question 1

Which of the following best describes a sound level of intensity 1 W/m2?

Accepted Answer

A)  extremely loud 
B)  about that of a power mower 
C)  normal conversation 
D)  like a whisper 
A)  extremely loud 
B)  about that of a power mower 
C)  normal conversation 
D)  like a whisper

Question 2

The term "timbre" refers to which of the following?

Accepted Answer

A)  Any musical instrument made primarily of wood. 
B)  The quality of sound from instruments due to the mixture of harmonics. 
C)  Instruments that have valves. 
D)  An instrument made in France. 
A)  Any musical instrument made primarily of wood. 
B)  The quality of sound from instruments due to the mixture of harmonics. 
C)  Instruments that have valves. 
D)  An instrument made in France.

Question 3

When two sound waves are out of phase by ____,destructive interference will occur.

Accepted Answer

A)  20° 
B)  210° 
C)  1,260° 
D)  1,440° 
E)  ​1,330° 
A)  20° 
B)  210° 
C)  1,260° 
D)  1,440° 
E)  ​1,330°

Question 4

The frequency separating audible waves and ultrasonic waves is considered to be 25 kHz.What wavelength in air at room temperature is associated with this frequency? (Assume the speed of sound to be 450 m/s. )

Accepted Answer

A)  1.8 cm 
B)  81 cm. 
C)  45 cm 
D)  81 cm 
E)  ​112.5 cm 
A)  1.8 cm 
B)  81 cm. 
C)  45 cm 
D)  81 cm 
E)  ​112.5 cm

Question 5

The Doppler shift of ultrasonic waves can measure the speed of blood in an artery.If the frequency of the stationary source is 95 kHz and the reflected sound has a Doppler shift of 150 Hz,what is the blood flow speed? (The speed of sound inside the body is 1 500 m/s. )

Accepted Answer

A)  1 m/s 
B)  1.2 m/s 
C)  2.4 m/s 
D)  3.6 m/s 
E)  ​5.3 m/s 
A)  1 m/s 
B)  1.2 m/s 
C)  2.4 m/s 
D)  3.6 m/s 
E)  ​5.3 m/s

Question 6

For a standing wave in an air column in a pipe that is open at both ends,there must be at least:

Accepted Answer

A)  one node and one antinode. 
B)  two nodes and one antinode. 
C)  two antinodes and one node. 
D)  two nodes and two antinodes. 
A)  one node and one antinode. 
B)  two nodes and one antinode. 
C)  two antinodes and one node. 
D)  two nodes and two antinodes.

Question 7

Quintupling the power output from a speaker emitting a single frequency will result in what increase in loudness?

Accepted Answer

A)  16.1 dB 
B)  6 dB 
C)  7.0 dB 
D)  2 dB 
E)  ​1 dB 
A)  16.1 dB 
B)  6 dB 
C)  7.0 dB 
D)  2 dB 
E)  ​1 dB

Question 8

Quadrupling the distance between sound source and a listener will change the intensity,as detected by the listener,by what factor?

Accepted Answer

A)  1/16 
B)  0.25 
C)  4 
D)  16 
E)  ​2.0 
A)  1/16 
B)  0.25 
C)  4 
D)  16 
E)  ​2.0

Question 9

When a sine wave is used to represent a sound wave,the crest corresponds to:

Accepted Answer

A)  rarefaction. 
B)  condensation. 
C)  point where molecules vibrate at a right angle to the direction of wave travel. 
D)  region of low elasticity. 
A)  rarefaction. 
B)  condensation. 
C)  point where molecules vibrate at a right angle to the direction of wave travel. 
D)  region of low elasticity.

Question 10

A plane is traveling at Mach 0.93 through air at a temperature of 0°C.What is the plane's speed? (Speed of sound at 0°C is 331 m/s. )

Accepted Answer

A)  308 m/s 
B)  331 m/s 
C)  424 m/s 
D)  93 m/s 
E)  ​Mach number is undefined at 0°C. 
A)  308 m/s 
B)  331 m/s 
C)  424 m/s 
D)  93 m/s 
E)  ​Mach number is undefined at 0°C.

Question 11

A 520-Hz whistle is moved toward a listener at a speed of 50 m/s.At the same time,the listener moves at a speed of 70 m/s in a direction away from the whistle.What is the apparent frequency heard by the listener? (The speed of sound is 340 m/s. )

Accepted Answer

A)  444 Hz 
B)  484 Hz 
C)  735 Hz 
D)  360 Hz 
E)  ​610 Hz 
A)  444 Hz 
B)  484 Hz 
C)  735 Hz 
D)  360 Hz 
E)  ​610 Hz

Question 12

For a standing wave on a string the wavelength must equal:

Accepted Answer

A)  the distance between adjacent nodes. 
B)  the distance between adjacent antinodes. 
C)  twice the distance between adjacent nodes. 
D)  the distance between supports. 
A)  the distance between adjacent nodes. 
B)  the distance between adjacent antinodes. 
C)  twice the distance between adjacent nodes. 
D)  the distance between supports.

Question 13

A vibrating guitar string emits a tone simultaneously with one from a 485-Hz tuning fork.If a beat frequency of 4 Hz results,what is the frequency of vibration of the string?

Accepted Answer

A)  1,940 Hz 
B)  489 Hz 
C)  481 Hz 
D)  ​244.5 
E)  ​Either choice b or c is valid. 
A)  1,940 Hz 
B)  489 Hz 
C)  481 Hz 
D)  ​244.5 
E)  ​Either choice b or c is valid.

Question 14

A child sits on a swing supported by ropes of length 3 m.With what frequency will she need to apply the driving force to maintain swinging?

Accepted Answer

A)  0.29 Hz 
B)  0.58 Hz 
C)  1.74 Hz 
D)  3.48 Hz 
E)  ​5.44 Hz 
A)  0.29 Hz 
B)  0.58 Hz 
C)  1.74 Hz 
D)  3.48 Hz 
E)  ​5.44 Hz

Question 15

What is the lowest frequency that will resonate in an organ pipe 4 m in length,closed at one end? The speed of sound in air is 340 m/s.

Accepted Answer

A)  21.3 Hz 
B)  42.5 Hz 
C)  85.0 Hz 
D)  1,360 Hz 
E)  ​2,720 Hz 
A)  21.3 Hz 
B)  42.5 Hz 
C)  85.0 Hz 
D)  1,360 Hz 
E)  ​2,720 Hz

Question 16

A flute behaves like a tube open at both ends.If its length is 62.9 cm,and the speed of sound is 340 m/s,what is its fundamental frequency in Hz?

Accepted Answer

A)  135 Hz 
B)  157 Hz 
C)  629 Hz 
D)  270 Hz 
E)  ​541 Hz 
A)  135 Hz 
B)  157 Hz 
C)  629 Hz 
D)  270 Hz 
E)  ​541 Hz

Question 17

A phase difference of 100° corresponds to what wavelength difference?

Accepted Answer

A)  5λ 
B) 
  λ 
C) 
  λ 
D) 
  λ 
E)  ​100λ 
A)  5λ 
B) 
  λ 
C) 
  λ 
D) 
  λ 
E)  ​100λ

Question 18

The lower A on a piano has a frequency of 30 Hz.If the tension in the 2-m-long string is 318 N and one-half wavelength occupies the string,what is the mass of the string?

Accepted Answer

A)  88 g 
B)  22 g 
C)  18 g 
D)  44 g 
E)  ​91 g 
A)  88 g 
B)  22 g 
C)  18 g 
D)  44 g 
E)  ​91 g

Question 19

The intensity level of sound 18 m from a jet airliner is 120 dB.At what distance from the airplane will the sound intensity level be a tolerable 100 dB? (Assume spherical spreading of sound. )

Accepted Answer

A)  13 m 
B)  120 m 
C)  360 m 
D)  232 m 
E)  ​8 m 
A)  13 m 
B)  120 m 
C)  360 m 
D)  232 m 
E)  ​8 m

Question 20

As a train starts from rest and then accelerates down the track,coming toward me faster and faster,the speed of the sound waves coming toward me will be:

Accepted Answer

A)  slower than the normal speed of sound in air. 
B)  equal to the normal speed of sound in air. 
C)  some constant speed faster than the normal speed of sound in air. 
D)  faster and faster. 
A)  slower than the normal speed of sound in air. 
B)  equal to the normal speed of sound in air. 
C)  some constant speed faster than the normal speed of sound in air. 
D)  faster and faster.

Exam 14: Sound

Which of the following best describes a sound level of intensity 1 W/m2?

The term "timbre" refers to which of the following?

When two sound waves are out of phase by ____,destructive interference will occur.

The frequency separating audible waves and ultrasonic waves is considered to be 25 kHz.What wavelength in air at room temperature is associated with this frequency? (Assume the speed of sound to be 450 m/s. )

The Doppler shift of ultrasonic waves can measure the speed of blood in an artery.If the frequency of the stationary source is 95 kHz and the reflected sound has a Doppler shift of 150 Hz,what is the blood flow speed? (The speed of sound inside the body is 1 500 m/s. )

For a standing wave in an air column in a pipe that is open at both ends,there must be at least:

Quintupling the power output from a speaker emitting a single frequency will result in what increase in loudness?

Quadrupling the distance between sound source and a listener will change the intensity,as detected by the listener,by what factor?

When a sine wave is used to represent a sound wave,the crest corresponds to:

A plane is traveling at Mach 0.93 through air at a temperature of 0°C.What is the plane's speed? (Speed of sound at 0°C is 331 m/s. )

A 520-Hz whistle is moved toward a listener at a speed of 50 m/s.At the same time,the listener moves at a speed of 70 m/s in a direction away from the whistle.What is the apparent frequency heard by the listener? (The speed of sound is 340 m/s. )

For a standing wave on a string the wavelength must equal:

A vibrating guitar string emits a tone simultaneously with one from a 485-Hz tuning fork.If a beat frequency of 4 Hz results,what is the frequency of vibration of the string?

A child sits on a swing supported by ropes of length 3 m.With what frequency will she need to apply the driving force to maintain swinging?

What is the lowest frequency that will resonate in an organ pipe 4 m in length,closed at one end? The speed of sound in air is 340 m/s.

A flute behaves like a tube open at both ends.If its length is 62.9 cm,and the speed of sound is 340 m/s,what is its fundamental frequency in Hz?

A phase difference of 100° corresponds to what wavelength difference?

The lower A on a piano has a frequency of 30 Hz.If the tension in the 2-m-long string is 318 N and one-half wavelength occupies the string,what is the mass of the string?

The intensity level of sound 18 m from a jet airliner is 120 dB.At what distance from the airplane will the sound intensity level be a tolerable 100 dB? (Assume spherical spreading of sound. )

As a train starts from rest and then accelerates down the track,coming toward me faster and faster,the speed of the sound waves coming toward me will be:

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

Which of the following best describes a sound level of intensity 1 W/m²?