Question 1

Crests of an ocean wave pass a pier every  
If the waves are moving at  
What is the wavelength of the ocean waves?

Accepted Answer

A) 56 m 
B) 28 m 
C) 64 m 
D) 48 m 
A) 56 m 
B) 28 m 
C) 64 m 
D) 48 m

Question 2

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. )

Accepted Answer

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. 
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.

Question 3

The lowest tone to resonate in a pipe of length L that is closed at one end but open at the other end is 200 Hz.Which one of the following frequencies will not resonate in that pipe?

Accepted Answer

A) 200 Hz 
B) 400 Hz 
C) 600 Hz 
D) 1000 Hz 
E) 1400 Hz 
A) 200 Hz 
B) 400 Hz 
C) 600 Hz 
D) 1000 Hz 
E) 1400 Hz

Question 4

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?

Accepted Answer

A) 890 Hz 
B) 920 Hz 
C) 1000 Hz 
D) 1200 Hz 
E) 1500 Hz 
A) 890 Hz 
B) 920 Hz 
C) 1000 Hz 
D) 1200 Hz 
E) 1500 Hz

Question 5

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?

Accepted Answer

A) 912 Hz 
B) 919 Hz 
C) 1000 Hz 
D) 1090 Hz 
A) 912 Hz 
B) 919 Hz 
C) 1000 Hz 
D) 1090 Hz

Question 6

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.

Accepted Answer

A) 26 m/s 
B) 27 m/s 
C) 28 m/s 
D) 29 m/s 
E) 30 m/s 
A) 26 m/s 
B) 27 m/s 
C) 28 m/s 
D) 29 m/s 
E) 30 m/s

Question 7

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. )

Accepted Answer

A) frequency 
B) amplitude 
C) wavelength 
D) period 
E) loudness 
A) frequency 
B) amplitude 
C) wavelength 
D) period 
E) loudness

Question 8

The sound intensity level 5.0 m from a point source is 95 dB.At what distance will it be 75 dB?

Accepted Answer

A) 25 m 
B) 50 m 
C) 75 m 
D) 225 m 
A) 25 m 
B) 50 m 
C) 75 m 
D) 225 m

Question 9

One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz,and the next higher harmonic has a frequency of 576 Hz.What is the fundamental frequency of the air column in this tube?

Accepted Answer

A) 32 Hz 
B) 64 Hz 
C) 88 Hz 
D) 128 Hz 
E) 256 Hz 
A) 32 Hz 
B) 64 Hz 
C) 88 Hz 
D) 128 Hz 
E) 256 Hz

Question 10

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?

Accepted Answer

A) v/2 
B) v/   
C) v   
D) 2v 
E) 4v 
A) v/2 
B) v/   
C) v   
D) 2v 
E) 4v

Question 11

A string that is 0.15 m long and fixed at both ends is vibrating in its n = 5 harmonic.The sound from this string excites a pipe that is  
Long and open at both ends into its second overtone resonance.What is the distance between a node and an adjacent antinode,in the string? The speed of sound in air is 345 m/s.

Accepted Answer

A) 15 mm 
B) 7.5 mm 
C) 23 mm 
D) 30 mm 
E) 150 mm 
A) 15 mm 
B) 7.5 mm 
C) 23 mm 
D) 30 mm 
E) 150 mm

Question 12

A string that is 0.26 m long is vibrating in its n = 6 harmonic.The sound from this string excites a pipe that is  
Long and open at both ends into its second overtone resonance.What is the common resonant frequency of the string and the pipe? The speed of sound in air is 345 m/s.

Accepted Answer

A) 590 Hz 
B) 390 Hz 
C) 490 Hz 
D) 690 Hz 
E) 760 Hz 
A) 590 Hz 
B) 390 Hz 
C) 490 Hz 
D) 690 Hz 
E) 760 Hz

Question 13

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?

Accepted Answer

A) 100 km 
B) 200 km 
C) 300 km 
D) 400 km 
E) 500 km 
A) 100 km 
B) 200 km 
C) 300 km 
D) 400 km 
E) 500 km

Question 14

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

Accepted Answer

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. 
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.

Question 15

What characteristics of a sound wave are related to the "pitch" of a musical note? (There could be more than one correct choice. )

Accepted Answer

A) amplitude 
B) wavelength 
C) frequency 
D) period 
A) amplitude 
B) wavelength 
C) frequency 
D) period

Question 16

A 0.13-m string,fixed at both ends and vibrating in its n = 4 harmonic,excites a pipe that is 0.88 m.  Long and open at both ends,into its second overtone resonance.What is the speed of transverse waves on the string? The speed of sound in air is 345 m/s.

Accepted Answer

A) 38 m/s 
B) 36 m/s 
C) 34 m/s 
D) 32 m/s 
E) 30 m/s 
A) 38 m/s 
B) 36 m/s 
C) 34 m/s 
D) 32 m/s 
E) 30 m/s

Question 17

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/m2.

Accepted Answer

A) 550 m 
B) 660 m 
C) 830 m 
D) 940 m 
E) 1,100 m 
A) 550 m 
B) 660 m 
C) 830 m 
D) 940 m 
E) 1,100 m

Question 18

Two in-phase loudspeakers that emit sound with the same frequency are placed along a wall and are separated by a distance of 8.00 m.A person is standing 12.0 m away from the wall,equidistant from the loudspeakers.When the person moves 3.00 m parallel to the wall,she experiences destructive interference for the second time.What is the frequency of the sound? The speed of sound in air is 343 m/s.

Accepted Answer

A) 278 Hz 
B) 422 Hz 
C) 452 Hz 
D) 562 Hz 
E) 694 Hz 
A) 278 Hz 
B) 422 Hz 
C) 452 Hz 
D) 562 Hz 
E) 694 Hz

Question 19

Two pure tones are sounded together and a particular beat frequency is heard.What happens to the beat frequency if the frequency of one of the tones is increased?

Accepted Answer

A) It increases. 
B) It decreases. 
C) It does not change. 
D) It could either increase or decrease. 
A) It increases. 
B) It decreases. 
C) It does not change. 
D) It could either increase or decrease.

Question 20

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?

Accepted Answer

A) 444 Hz 
B) 439 Hz 
C) 364 Hz 
D) 361 Hz 
A) 444 Hz 
B) 439 Hz 
C) 364 Hz 
D) 361 Hz

Exam 14: Waves and Sound

Crests of an ocean wave pass a pier every If the waves are moving at What is the wavelength of the ocean waves?

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. )

The lowest tone to resonate in a pipe of length L that is closed at one end but open at the other end is 200 Hz.Which one of the following frequencies will not resonate in that pipe?

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 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?

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.

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. )

The sound intensity level 5.0 m from a point source is 95 dB.At what distance will it be 75 dB?

One of the harmonics of a column of air in a tube that is open at one end and closed at the other has a frequency of 448 Hz,and the next higher harmonic has a frequency of 576 Hz.What is the fundamental frequency of the air column in this tube?

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 string that is 0.26 m long is vibrating in its n = 6 harmonic.The sound from this string excites a pipe that is Long and open at both ends into its second overtone resonance.What is the common resonant frequency of the string and the pipe? The speed of sound in air is 345 m/s.

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

What characteristics of a sound wave are related to the "pitch" of a musical note? (There could be more than one correct choice. )

A 0.13-m string,fixed at both ends and vibrating in its n = 4 harmonic,excites a pipe that is 0.88 m. Long and open at both ends,into its second overtone resonance.What is the speed of transverse waves on the string? The speed of sound in air is 345 m/s.

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/m2.

Two pure tones are sounded together and a particular beat frequency is heard.What happens to the beat frequency if the frequency of one of the tones is increased?

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?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

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Physical Optics: Interference and Diffraction

Relativity

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Filters

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/m².