Question 1

A 25-g string is stretched with a tension of 43 N between two fixed points 12 m apart. What is the frequency of the second harmonic?

Accepted Answer

A)  6.0 Hz 
B)  12 Hz 
C)  18 Hz 
D)  24 Hz 
E)  36 Hz 
A)  6.0 Hz 
B)  12 Hz 
C)  18 Hz 
D)  24 Hz 
E)  36 Hz B

Question 2

In a resonating pipe that is open at one end and closed at the other end, there

Accepted Answer

A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at the open end and a displacement antinode at the closed end. 
D)  is a displacement node at the closed end and a displacement antinode at the open end. 
A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at the open end and a displacement antinode at the closed end. 
D)  is a displacement node at the closed end and a displacement antinode at the open end. D

Question 3

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 B

Question 4

A string that is 2.0 meters long is fixed at both ends and tightened until the wave speed is $18 \mathrm {~m} / \mathrm { s }$ What is the frequency of the standing wave shown in the figure?

Accepted Answer

A)  27 Hz 
B)  54 Hz 
C)  81 Hz 
D)  110 Hz 
A)  27 Hz 
B)  54 Hz 
C)  81 Hz 
D)  110 Hz

Question 5

An pipe of length L that is open at both ends is resonating at its fundamental frequency. Which statement about the sound is correct?

Accepted Answer

A)  The wavelength is 2L and there is a displacement node at the pipe's midpoint. 
B)  The wavelength is 2L and there is a displacement antinode at the pipe's midpoint. 
C)  The wavelength is L and there is a displacement node at the pipe's midpoint. 
D)  The wavelength is L and there is a displacement antinode at the pipe's midpoint. 
A)  The wavelength is 2L and there is a displacement node at the pipe's midpoint. 
B)  The wavelength is 2L and there is a displacement antinode at the pipe's midpoint. 
C)  The wavelength is L and there is a displacement node at the pipe's midpoint. 
D)  The wavelength is L and there is a displacement antinode at the pipe's midpoint.

Question 6

Two speakers are placed side by side and driven by the same frequency of 0.50 kHz. If the distance from a person to one speaker is 5.0 m and the person detects little or no sound, which of the following is a possible the distance from the person to the other speaker? The sound speed in the room is 340 m/s.

Accepted Answer

A)  7.7 m 
B)  8.1 m 
C)  8.4 m 
D)  9.1 m 
A)  7.7 m 
B)  8.1 m 
C)  8.4 m 
D)  9.1 m

Question 7

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 $0.82 \mathrm {~m}$ 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 8

A pipe that is 0.92 m long and open at both ends vibrates in the second overtone with a frequency of 584 ${~Hz}$ What is the speed of sound in the air in this pipe?

Accepted Answer

A)  358 m/s 
B)  349 m/s 
C)  353 m/s 
D)  344 m/s 
E)  363 m/s 
A)  358 m/s 
B)  349 m/s 
C)  353 m/s 
D)  344 m/s 
E)  363 m/s

Question 9

One of the harmonics of a column of air in a tube that is open at both ends 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

A guitar string 0.65 m long has a tension of 61 N and a mass per unit length of 3.0 g/m.
(a) What is the speed of waves on the string when it is plucked?
(b) What is the string's fundamental frequency of vibration when plucked?
(c) At what other frequencies will this string vibrate?

Accepted Answer

(a) 143 m/s 
(b) 110

Question 11

Two loudspeakers placed 6.00 m apart are driven in phase by an audio oscillator having a frequency range from 1908 Hz to 2471 Hz. A point P is located 4.70 m from one loudspeaker and 3.60 m from the other speaker. At what frequency of the oscillator does the sound reaching point P interfere constructively? The speed of sound is 344 m/s.

Accepted Answer

A)  2190 Hz 
B)  2420 Hz 
C)  2110 Hz 
D)  2340 Hz 
E)  2270 Hz 
A)  2190 Hz 
B)  2420 Hz 
C)  2110 Hz 
D)  2340 Hz 
E)  2270 Hz

Question 12

Two police cars have identical sirens that produce sound of frequency of 570 Hz. A stationary listener is standing between two cars. One car is parked and the other is approaching the listener and both have their sirens on. The listener measures 9.0 beats per second. Find the speed of the approaching police car. The speed of sound is 340 m/s.

Accepted Answer

The answer of Two police cars have identical sirens that...

Question 13

A 0.588-m string is tightly clamped at both ends. If the lowest standing wave frequency of the string is $326 \mathrm {~Hz}$ how fast do waves travel on this string?

Accepted Answer

A)  383 m/s 
B)  475 m/s 
C)  582 m/s 
D)  724 m/s 
A)  383 m/s 
B)  475 m/s 
C)  582 m/s 
D)  724 m/s

Question 14

Consider the standing wave on a guitar string and the sound wave generated by the string as a result of this vibration. What do these two waves have in common? (There may be more than one correct choice.)
A) They have the same wavelength.
B) They have the same speed.
C) They have the same frequency.
D) They have the same amplitude.
E) They have the same period.

Accepted Answer

The answer of Consider the standing wave on a guitar...

Question 15

In a resonating pipe that is open at both ends, there

Accepted Answer

A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at one end and a displacement antinode at the other end. 
D)  None of the above choices are correct. 
A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at one end and a displacement antinode at the other end. 
D)  None of the above choices are correct.

Question 16

When a guitar is tuned to adjust it pitch, what is it that is changed?

Accepted Answer

A)  The wavelength of the fundamental. 
B)  The frequency of the fundamental. 
C)  The amplitude of the fundamental. 
A)  The wavelength of the fundamental. 
B)  The frequency of the fundamental. 
C)  The amplitude of the fundamental.

Question 17

In a resonating pipe that is open at one end and closed at the other, there

Accepted Answer

A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at the open end and a displacement antinode at the closed end. 
D)  is a displacement node at the closed end and a displacement antinode at the open end. 
A)  are displacement nodes at each end. 
B)  are displacement antinodes at each end. 
C)  is a displacement node at the open end and a displacement antinode at the closed end. 
D)  is a displacement node at the closed end and a displacement antinode at the open end.

Question 18

A policeman in a stationary car measures the speed of approaching cars by means of an ultrasonic device that emits a sound with a frequency of 39.6 kHz. A car is approaching him at a speed of 35.0 m/s. The wave is reflected by the car and interferes with the emitted sound producing beats. What is the frequency of the beats when the speed of sound in air is 343 m/s?

Accepted Answer

A)  5000 Hz 
B)  4500 Hz 
C)  8490 Hz 
D)  9000 Hz 
E)  4250 Hz 
A)  5000 Hz 
B)  4500 Hz 
C)  8490 Hz 
D)  9000 Hz 
E)  4250 Hz

Question 19

A standing wave of the third overtone is induced in a 1.2-m pipe that is open at one end and closed at the other end. The speed of sound in the pipe is 340 m/s.
(a) How many antinodes are there in the standing wave pattern?
(b) What is the frequency of the sound produced by the pipe in this situation?

Accepted Answer

The answer of A standing wave of the third overtone...

Question 20

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.

Exam 16: Superposition and Standing Waves

A 25-g string is stretched with a tension of 43 N between two fixed points 12 m apart. What is the frequency of the second harmonic?

In a resonating pipe that is open at one end and closed at the other end, there

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?

A string that is 2.0 meters long is fixed at both ends and tightened until the wave speed is 18 m/s18 \mathrm {~m} / \mathrm { s }18 m/s What is the frequency of the standing wave shown in the figure?

An pipe of length L that is open at both ends is resonating at its fundamental frequency. Which statement about the sound is correct?

A pipe that is 0.92 m long and open at both ends vibrates in the second overtone with a frequency of 584 Hz{~Hz} Hz What is the speed of sound in the air in this pipe?

One of the harmonics of a column of air in a tube that is open at both ends 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?

A guitar string 0.65 m long has a tension of 61 N and a mass per unit length of 3.0 g/m. (a) What is the speed of waves on the string when it is plucked? (b) What is the string's fundamental frequency of vibration when plucked? (c) At what other frequencies will this string vibrate?

A 0.588-m string is tightly clamped at both ends. If the lowest standing wave frequency of the string is 326 Hz326 \mathrm {~Hz}326 Hz how fast do waves travel on this string?

In a resonating pipe that is open at both ends, there

When a guitar is tuned to adjust it pitch, what is it that is changed?

In a resonating pipe that is open at one end and closed at the other, there

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?

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A pipe that is 0.92 m long and open at both ends vibrates in the second overtone with a frequency of 584 ${~Hz}$ What is the speed of sound in the air in this pipe?

A 0.588-m string is tightly clamped at both ends. If the lowest standing wave frequency of the string is $326 \mathrm {~Hz}$ how fast do waves travel on this string?