Question 1

A standing wave in a pipe has nodes that are 1.2 m apart.What is the wavelength of the wave?

Accepted Answer

A) 0.6 m 
B) 1.2 m 
C) 1.8 m 
D) 2.4 m 
E) cannot tell without knowing which harmonic it is 
A) 0.6 m 
B) 1.2 m 
C) 1.8 m 
D) 2.4 m 
E) cannot tell without knowing which harmonic it is

Question 2

A microphone of surface area 2.0 cm2 absorbs 1.1 mW of sound.What is the intensity of sound hitting the microphone?

Accepted Answer

A) 2.2 x 10-5 W/m2  
B) 0.55 W/m2  
C) 2.2 W/m2 
D) 2.8 W/m2 
E) 5.5 W/m2 
A) 2.2 x 10-5 W/m2  
B) 0.55 W/m2  
C) 2.2 W/m2 
D) 2.8 W/m2 
E) 5.5 W/m2

Question 3

The diagram shows four situations in which a source of sound S and a detector D are either moving or stationary.The arrows indicate the directions of motion.The speeds (when not zero)are all the same.(Note that the detector in situation 3 is stationary).Rank the situations according to the apparent frequency of the source, lowest to highest.

Accepted Answer

A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 1, 3, 4, 2 
D) 2, 1, 4, 3 
E) None of the above 
A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 1, 3, 4, 2 
D) 2, 1, 4, 3 
E) None of the above

Question 4

The difference between transverse and longitudinal waves:

Accepted Answer

A) depends on the frequency of the wave 
B) depends on the wavelength of the wave 
C) depends on the direction of propagation of the wave 
D) depends on the direction of oscillation of the medium relative to the direction of propagation of the wave 
E) there is no difference, they are just two ways of describing the same phenomenon 
A) depends on the frequency of the wave 
B) depends on the wavelength of the wave 
C) depends on the direction of propagation of the wave 
D) depends on the direction of oscillation of the medium relative to the direction of propagation of the wave 
E) there is no difference, they are just two ways of describing the same phenomenon

Question 5

The sound level at a point P is 14 db below the sound level at a point 1.0 m from a point source.Assuming the intensity from a point source drops off like the inverse square of the distance, the distance from the source to point P is:

Accepted Answer

A) 4.0 cm 
B) 20 m 
C) 2.0 m 
D) 5.0 m 
E) 25 m 
A) 4.0 cm 
B) 20 m 
C) 2.0 m 
D) 5.0 m 
E) 25 m

Question 6

Beats in sound occur when:

Accepted Answer

A) two waves of the same frequency interfere 
B) two waves of slightly different frequency interfere 
C) a reflected wave interferes with an incident wave 
D) waves travel in two media having slightly different sound velocities 
E) source and observer are in relative motion 
A) two waves of the same frequency interfere 
B) two waves of slightly different frequency interfere 
C) a reflected wave interferes with an incident wave 
D) waves travel in two media having slightly different sound velocities 
E) source and observer are in relative motion

Question 7

A sound wave has a wavelength of 3.0 m.The distance from a compression center to the adjacent rarefaction center is:

Accepted Answer

A) 0.75 m 
B) 1.5 m 
C) 3.0 m 
D) need to know wave speed 
E) need to know frequency 
A) 0.75 m 
B) 1.5 m 
C) 3.0 m 
D) need to know wave speed 
E) need to know frequency

Question 8

Two stationary tuning forks (350 and 352 Hz)are struck simultaneously.The resulting sound is observed to:

Accepted Answer

A) beat with a frequency of 2 beats/s 
B) beat with a frequency of 351 beats/s 
C) be loud but not beat 
D) be Doppler shifted by 2 Hz 
E) have a frequency of 702 Hz 
A) beat with a frequency of 2 beats/s 
B) beat with a frequency of 351 beats/s 
C) be loud but not beat 
D) be Doppler shifted by 2 Hz 
E) have a frequency of 702 Hz

Question 9

The longitudinal displacement of a mass element in a medium as a sound wave passes through it is given by s = sm cos (kx - ωt).Consider a sound wave of frequency 440 Hz and wavelength 0.75m.If sm = 12 µm, how long does it take an element of air to move from a displacement of 12 µm to a displacement of 0 µm?

Accepted Answer

A) 0.57 ms 
B) 1.1 ms 
C) 2.3 ms 
D) 3.4 ms 
E) 4.6 ms 
A) 0.57 ms 
B) 1.1 ms 
C) 2.3 ms 
D) 3.4 ms 
E) 4.6 ms

Question 10

This graph shows the position of an element of air as a function of time as a sound wave passes through it.Which letter corresponds to the period of the wave?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 11

The Doppler shift formula for the frequency detected is   where f ' is the frequency emitted, v is the speed of sound, vD is the speed of the detector, and vs is the speed of the source.Suppose the source is traveling at 5 m/s away from the detector, the detector is traveling at 7 m/s toward the source, and there is a 3 m/s wind blowing from the source toward the detector.The values that should be substituted into the Doppler shift equation are:

Accepted Answer

A) vD = 7 m/s and vs = 5 m/s 
B) vD = 10 m/s and vs = 8 m/s 
C) vD = 4 m/s and vs = 2 m/s 
D) vD = 10 m/s and vs = 2 m/s 
E) vD = 4 m/s and vs = 8 m/s 
A) vD = 7 m/s and vs = 5 m/s 
B) vD = 10 m/s and vs = 8 m/s 
C) vD = 4 m/s and vs = 2 m/s 
D) vD = 10 m/s and vs = 2 m/s 
E) vD = 4 m/s and vs = 8 m/s

Question 12

Two small identical speakers are connected (in phase)to the same source.The speakers are 3 m apart and at ear level.An observer stands at X, 4 m in front of one speaker as shown.The sound she hears will be most intense if the wavelength is:

Accepted Answer

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

Question 13

In order for two sound waves to produce audible beats, it is essential that the two waves have:

Accepted Answer

A) the same amplitude 
B) the same frequency 
C) the same number of overtones 
D) slightly different amplitudes 
E) slightly different frequencies 
A) the same amplitude 
B) the same frequency 
C) the same number of overtones 
D) slightly different amplitudes 
E) slightly different frequencies

Question 14

When listening to tuning forks of frequency 256 Hz and 260 Hz, one hears the following number of beats per second:

Accepted Answer

A) 0 
B) 2 
C) 4 
D) 8 
E) 258 
A) 0 
B) 2 
C) 4 
D) 8 
E) 258

Question 15

The bulk modulus of water is 2.2 x 109 Pa, and its density is 1.0 x 103 kg/m3.What is the speed of sound in water?

Accepted Answer

A) 1.5 x 103 m/s 
B) 2.2 x 103 m/s 
C) 3.5 x 103 m/s 
D) 4.5 x 103 m/s 
E) 2.2 x 106 m/s 
A) 1.5 x 103 m/s 
B) 2.2 x 103 m/s 
C) 3.5 x 103 m/s 
D) 4.5 x 103 m/s 
E) 2.2 x 106 m/s

Question 16

An organ pipe with both ends open is 0.85 m long.Assuming that the speed of sound is 340 m/s, the frequency of the third harmonic of this pipe is:

Accepted Answer

A) 200 Hz 
B) 300 Hz 
C) 400 Hz 
D) 600 Hz 
E) none of these 
A) 200 Hz 
B) 300 Hz 
C) 400 Hz 
D) 600 Hz 
E) none of these

Question 17

Take the speed of sound to be 340 m/s.A thunder clap is heard about 3 s after the lightning is seen.The source of both light and sound is:

Accepted Answer

A) moving overhead faster than the speed of sound 
B) emitting a much higher frequency than is heard 
C) emitting a much lower frequency than is heard 
D) about 1000 m away 
E) much more than 1000 m away 
A) moving overhead faster than the speed of sound 
B) emitting a much higher frequency than is heard 
C) emitting a much lower frequency than is heard 
D) about 1000 m away 
E) much more than 1000 m away

Question 18

A source emits sound with a frequency of 1000 Hz.It is moving at 20 m/s toward a stationary reflecting wall.If the speed of sound is 340 m/s an observer at rest directly behind the source hears a beat frequency of:

Accepted Answer

A) 3.0 Hz 
B) 55 Hz 
C) 63 Hz 
D) 114 Hz 
E) 118 Hz 
A) 3.0 Hz 
B) 55 Hz 
C) 63 Hz 
D) 114 Hz 
E) 118 Hz

Question 19

Two notes are an octave apart.The ratio of their frequencies is:

Accepted Answer

A) 8 
B) 10 
C)    
D) 2 
E)    
A) 8 
B) 10 
C)    
D) 2 
E)

Question 20

Two waves are out of phase by half a wavelength.What is this in radians?

Accepted Answer

A) π/6 
B) π/4 
C) π/2 
D) π 
E) 3π/2 
A) π/6 
B) π/4 
C) π/2 
D) π 
E) 3π/2

Exam 17: Waves

A standing wave in a pipe has nodes that are 1.2 m apart.What is the wavelength of the wave?

A microphone of surface area 2.0 cm2 absorbs 1.1 mW of sound.What is the intensity of sound hitting the microphone?

The difference between transverse and longitudinal waves:

The sound level at a point P is 14 db below the sound level at a point 1.0 m from a point source.Assuming the intensity from a point source drops off like the inverse square of the distance, the distance from the source to point P is:

Beats in sound occur when:

A sound wave has a wavelength of 3.0 m.The distance from a compression center to the adjacent rarefaction center is:

Two stationary tuning forks (350 and 352 Hz)are struck simultaneously.The resulting sound is observed to:

This graph shows the position of an element of air as a function of time as a sound wave passes through it.Which letter corresponds to the period of the wave?

Two small identical speakers are connected (in phase)to the same source.The speakers are 3 m apart and at ear level.An observer stands at X, 4 m in front of one speaker as shown.The sound she hears will be most intense if the wavelength is:

In order for two sound waves to produce audible beats, it is essential that the two waves have:

When listening to tuning forks of frequency 256 Hz and 260 Hz, one hears the following number of beats per second:

The bulk modulus of water is 2.2 x 109 Pa, and its density is 1.0 x 103 kg/m3.What is the speed of sound in water?

An organ pipe with both ends open is 0.85 m long.Assuming that the speed of sound is 340 m/s, the frequency of the third harmonic of this pipe is:

Take the speed of sound to be 340 m/s.A thunder clap is heard about 3 s after the lightning is seen.The source of both light and sound is:

A source emits sound with a frequency of 1000 Hz.It is moving at 20 m/s toward a stationary reflecting wall.If the speed of sound is 340 m/s an observer at rest directly behind the source hears a beat frequency of:

Two notes are an octave apart.The ratio of their frequencies is:

Two waves are out of phase by half a wavelength.What is this in radians?

Measurement

Motion Along a Straight Line

Vectors

Motion in Two and Three Dimensions

Force and Motion

Force and Motion

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

Equilibrium and Elasticity

Gravitation

Fluids

Oscillations

Waves

Temperature, Heat, and the First Law of Thermodynamics

The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Coulombs Law

Electric Fields

Gauss Law

Electric Potential

Capacitance

Current and Resistance

Circuits

Magnetic Fields

Magnetic Fields Due to Currents

Induction and Inductance

Electromagnetic Oscillations and Alternating Current

Maxwells Equations; Magnetism of Matter

Electromagnetic Waves

Images

Interference 1

Diffraction

Relativity

Photons and Matter Waves

More About Matter Waves

All About Atoms

Conduction of Electricity in Solids

Energy From the Nucleus

Quarks, Leptons, and the Big Bang

Filters

A microphone of surface area 2.0 cm² absorbs 1.1 mW of sound.What is the intensity of sound hitting the microphone?

The bulk modulus of water is 2.2 x 10⁹ Pa, and its density is 1.0 x 10³ kg/m³.What is the speed of sound in water?