Chapter 16: Superposition and Standing Waves The interference of

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Transcript Chapter 16: Superposition and Standing Waves The interference of

Sketch

A

shows two identical pulses traveling in opposite directions along a string, each with a speed of 1.0 cm/s. After 4.0 s, the string will look like which of the other sketches?

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

Sketch

A

shows two identical pulses traveling in opposite directions along a string, each with a speed of 1.0 cm/s. After 4.0 s, the string will look like which of the other sketches?

A. 1

B. 2

C. 3 D. 4 E. 5

Why does your voice change pitch when you speak after inhaling the contents of a helium-filled balloon? A. The helium decreases the effective length of your vocal cords, so their fundamental frequency is increased.

B. The helium increases the stiffness of your vocal cords, so their fundamental frequency is increased.

C. The speed of sound in helium is higher than the speed of sound in air, so the fundamental frequency of your throat and mouth cavity is increased.

D. The speed of sound in helium is lower than the speed of sound in air, so the frequency of the sound released into the air is increased.

E. Helium is a lighter gas than air, so the resulting buoyancy force causes the pitch to rise.

Why does your voice change pitch when you speak after inhaling the contents of a helium-filled balloon? A. The helium decreases the effective length of your vocal cords, so their fundamental frequency is increased.

B. The helium increases the stiffness of your vocal cords, so their fundamental frequency is increased.

C. The speed of sound in helium is higher than the speed of sound in air, so the fundamental frequency of your throat and mouth cavity is increased.

D. The speed of sound in helium is lower than the speed of sound in air, so the frequency of the sound released into the air is increased.

E. Helium is a lighter gas than air, so the resulting buoyancy force causes the pitch to rise.

The figure represents a string of length

L

, fixed at both ends, vibrating in several harmonics. Which string shows the 4th harmonic?

The figure represents a string of length

L

, fixed at both ends, vibrating in several harmonics. Which string shows the 4th harmonic?

The figure represents a string of length

L

, fixed at both ends, vibrating in several harmonics. Which string shows the 3rd harmonic?

The figure represents a string of length

L

, fixed at both ends, vibrating in several harmonics. Which string shows the 3rd harmonic?

The figure shows several modes of vibration of a string fixed at both ends. The mode of vibration that represents the fifth harmonic is A. 1 B. 2 C. 3 D. 4 E. None of these is correct.

The figure shows several modes of vibration of a string fixed at both ends. The mode of vibration that represents the fifth harmonic is A. 1 B. 2 C. 3 D. 4

E. None of these is correct.

The fundamental frequency of a vibrating string is

f

1 . If the tension in the string is doubled, the fundamental frequency becomes A B C D E .

.

.

.

.

f

1 2

f

1 2

f

1 2

f

1 2

f

1

The fundamental frequency of a vibrating string is

f

1 . If the tension in the string is doubled, the fundamental frequency becomes A B C D E .

.

.

.

.

f

1 2

f

1 2

f

1 2

f

1 2

f

1

The fundamental frequency of a vibrating string is

f

1 . If the tension in the string is increased by 50% while the linear density is held constant, the fundamental frequency becomes A.

f

1 B. 1.2

f

1 C. 1.5

f

1 D. 1.7

f

1 E. 2

f

1

The fundamental frequency of a vibrating string is

f

1 . If the tension in the string is increased by 50% while the linear density is held constant, the fundamental frequency becomes A.

f

1

B. 1.2f 1

C. 1.5

f

1 D. 1.7

f

1 E. 2

f

1

A stretched string is fixed at points 1 and 5. When it is vibrating at the second harmonic frequency, the nodes of the standing wave are at points A. 1 and 5. B. 1, 3, and 5. C. 1 and 3. D. 2 and 4. E. 1, 2, 3, 4, and 5.

A stretched string is fixed at points 1 and 5. When it is vibrating at the second harmonic frequency, the nodes of the standing wave are at points A. 1 and 5.

B. 1, 3, and 5.

C. 1 and 3. D. 2 and 4. E. 1, 2, 3, 4, and 5.

A stretched string is fixed at points 1 and 5. When it is vibrating in its first harmonic frequency, the nodes are at points A. 1 and 5 only. B. 1, 3, and 5. C. 2 and 4. D. 2, 3, and 4. E. 1, 2, 3, 4, and 5.

A stretched string is fixed at points 1 and 5. When it is vibrating in its first harmonic frequency, the nodes are at points

A. 1 and 5 only.

B. 1, 3, and 5. C. 2 and 4. D. 2, 3, and 4. E. 1, 2, 3, 4, and 5.

The figure shows a standing wave in a pipe that is closed at one end. The frequency associated with this wave pattern is called the A. first harmonic. B. second harmonic. C. third harmonic. D. fourth harmonic. E. fifth harmonic.

The figure shows a standing wave in a pipe that is closed at one end. The frequency associated with this wave pattern is called the A. first harmonic. B. second harmonic. C. third harmonic. D. fourth harmonic.

E. fifth harmonic.

Of the sound sources shown, that which is vibrating with its first harmonic is A. the whistle. B. the organ pipe. C. the vibrating string. D. the vibrating rod. E. None of these.

Of the sound sources shown, that which is vibrating with its first harmonic is A. the whistle. B. the organ pipe. C. the vibrating string. D. the vibrating rod.

E. None of these.

Of the sound sources shown, that which is vibrating with its first harmonic is the A. whistle. B. organ pipe. C. vibrating string. D. vibrating rod. E. vibrating spring.

Of the sound sources shown, that which is vibrating with its first harmonic is the

A. whistle.

B. organ pipe. C. vibrating string. D. vibrating rod. E. vibrating spring.

When an organ pipe, which is closed at one end only, vibrates with a frequency that is three times its fundamental (first harmonic) frequency, A. the sound produced travels at three times its former speed. B. the sound produced is its fifth harmonic. C. beats are produced. D. the sound produced has one-third its former wavelength. E. the closed end is a displacement antinode.

When an organ pipe, which is closed at one end only, vibrates with a frequency that is three times its fundamental (first harmonic) frequency, A. the sound produced travels at three times its former speed. B. the sound produced is its fifth harmonic. C. beats are produced.

D. the sound produced has one-third its former wavelength.

E. the closed end is a displacement antinode.

The air in a closed organ pipe vibrates as shown. The length of the pipe is 3.0 m. The frequency of vibration is 80 Hz. The speed of sound in the pipe is approximately A. 80 m/s B. 0.16 km/s C. 0.24 km/s D. 0.32 km/s E. 0.96 km/s

The air in a closed organ pipe vibrates as shown. The length of the pipe is 3.0 m. The frequency of vibration is 80 Hz. The speed of sound in the pipe is approximately A. 80 m/s B. 0.16 km/s C. 0.24 km/s

D. 0.32 km/s

E. 0.96 km/s

A string fixed at both ends is vibrating in a standing wave. There are three nodes between the ends of the string, not including those on the ends. The string is vibrating at a frequency that is its A. fundamental. B. second harmonic. C. third harmonic. D. fourth harmonic. E. fifth harmonic.

A string fixed at both ends is vibrating in a standing wave. There are three nodes between the ends of the string, not including those on the ends. The string is vibrating at a frequency that is its A. fundamental. B. second harmonic. C. third harmonic.

D. fourth harmonic.

E. fifth harmonic.

On a standing-wave pattern, the distance between two consecutive nodes is

d

. The wavelength is A.

B.

d

/2

d

C. 3

d

/2 D. 2

d

E. 4

d

On a standing-wave pattern, the distance between two consecutive nodes is

d

. The wavelength is A.

B.

d

/2

d

C. 3

d

/2

D. 2d

E. 4

d

A stretched string of length

L

, fixed at both ends, is vibrating in its third harmonic. How far from the end of the string can the blade of a screwdriver be placed against the string without disturbing the amplitude of the vibration? A.

B.

L

/6

L

/4 C.

L

/5 D.

L

/2 E.

L

/3

A stretched string of length

L

, fixed at both ends, is vibrating in its third harmonic. How far from the end of the string can the blade of a screwdriver be placed against the string without disturbing the amplitude of the vibration? A.

B.

L

/6

L

/4 C.

L

/5 D.

L

/2

E. L/3

In a pipe that is open at one end and closed at the other and that has a fundamental frequency of 256 Hz, which of the following frequencies cannot be produced? A. 768 Hz B. 1.28 kHz C. 5.12 kHz D. 19.7 kHz E. All of these can be produced.

In a pipe that is open at one end and closed at the other and that has a fundamental frequency of 256 Hz, which of the following frequencies cannot be produced? A. 768 Hz B. 1.28 kHz

C. 5.12 kHz

D. 19.7 kHz E. All of these can be produced.

The fundamental frequency of a pipe that has one end closed is 256 Hz. When both ends of the same pipe are opened, the fundamental frequency is A. 64.0 Hz B. 128 Hz C. 256 Hz D. 512 Hz E. 1.02 kHz

The fundamental frequency of a pipe that has one end closed is 256 Hz. When both ends of the same pipe are opened, the fundamental frequency is A. 64.0 Hz

B. 128 Hz

C. 256 Hz D. 512 Hz E. 1.02 kHz

A 1.00 m string fixed at both ends vibrates in its fundamental mode at 440 Hz. What is the speed of the waves on this string? A. 220 m/s B. 440 m/s C. 660 m/s D. 880 m/s E. 1.10 km/s

A 1.00 m string fixed at both ends vibrates in its fundamental mode at 440 Hz. What is the speed of the waves on this string? A. 220 m/s B. 440 m/s C. 660 m/s

D. 880 m/s

E. 1.10 km/s

The sound wave in an organ tube shown has a wavelength that is equal to the distance between A. A and B. B. A and C. C. the nodes farthest apart. D. the antinodes farthest apart. E. None of these is correct.

The sound wave in an organ tube shown has a wavelength that is equal to the distance between A. A and B. B. A and C. C. the nodes farthest apart.

D. the antinodes farthest apart.

E. None of these is correct.