Deck 12: The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Question 1

A wave on a string has a wavelength of 0.90 m at a frequency of 600 Hz.If a new wave at a frequency of 300 Hz is established in this same string under the same tension,what is the new wavelength?

A) 2.7 m
B) 1.8 m
C) 0.45 m
D) 0.30 m

Answer 1

1.8 m

Question 2

A speaker designed to emit spherical sound waves is producing a sound intensity of 8 W/m² at a distance of 1 m from the speaker.What would be the intensity of this sound at a distance of 2 m from the speaker?

A)
W/m²
B) 4 W/m²
C)
W/m²
​
D) 2 W/m²

Answer 2

2 W/m²

Question 3

A string is strung horizontally with a fixed tension.A wave of frequency 100 Hz is sent along the string,and it has a wave speed of 100 m/s.Then a second wave,one of frequency 200 Hz,is sent along the string.What is the wave speed of the second wave?

A) 25.0 m/s
B) 50.0 m/s
C) 70.7 m/s
D) 100 m/s

Answer 3

100 m/s

Question 4

If the speed of a wave on a violin string is 400 m/s,what will be the speed of the wave if the tension in the string is halved?

A) 100 m/s
B) 200 m/s
C) 280 m/s
D) 570 m/s

Question 5

A traveling wave train has wavelength 1.0 m and speed 20 m/s.Find the wave frequency.

A) 0.025 Hz
B) 20 Hz
C) 40 Hz
D) 10 Hz

Question 6

Doubling the mass per unit length of a guitar string will result in changing the wave speed in the string by what factor?

A) 1.41
B) 1.00 (i.e. ,no change)
C) 0.71
D) 2.00

Question 7

Waves propagate at 4.0 m/s along a stretched string.The end of the string is vibrated up and down once every 3.0 s.What is the wavelength of the waves that travel along the string?

A) 3.0 m
B) 12 m
C) 6.0 m
D) 2.7 m

Question 8

Wave #1 has frequency f₁ and wavelength λ₁.Wave #2 has frequency f₂ = 6 f₁ and wavelength λ₂ = 2λ₁.How does the speed v₂ of wave #2 compare with the speed v₁ of wave #1?

A) v₂ = 12v₁
B) v₂ = 6v₁
C) v₂ = 1.5v₁
D) v₂ = v₁/6

Question 9

A musical tone,sounded on a piano,has a frequency of 820 Hz and a wavelength in air of 0.400 m.What is the wave speed?

A) 587 m/s
B) 328 m/s
C) 235 m/s
D) 170 m/s

Question 10

Quadrupling both the tension in a guitar string and its mass per unit length will result in changing the wave speed in the string by what factor?

A) 4.00
B) 2.00
C) 1.00 (i.e. ,no change)
D) 0.50

Question 11

A wave is traveling in a string at 60 m/s.When the tension is then increased 60%,what will be the resulting wave speed?

A) also 60 m/s
B) 76 m/s
C) 71 m/s
D) 55 m/s

Question 12

Sound waves of a certain frequency in air having a wavelength of 1.9 m will have what wavelength in water? Take the speed of sound in air to be 340 m/s and in water to be 1 490 m/s.

A) 0.57 m
B) 1.9 m
C) 8.3 m
D) 11 m

Question 13

A long string is pulled so that the tension in it increases by a factor of four.If the change in length is negligible,by what factor does the wave speed change?

A) 0.25
B) 0.50
C) 2.0
D) 4.0

Question 14

Transverse waves travel with a speed of 283 m/s along a taut copper wire that has a diameter of 1.50 mm.What is the tension in the wire? (The density of copper is 8.93 g/cm³. )

A) 1890 N
B) 1260 N
C) 631 N
D) 315 N

Question 15

Bats can detect small objects such as insects that are of a size approximately that of one wavelength.If bats emit a chirp at a frequency of 50 kHz,and the speed of sound waves in air is 330 m/s,what is the smallest size insect they can detect?

A) 1.5 mm
B) 3.7 mm
C) 5.5 mm
D) 6.6 mm

Question 16

A wave travels in a string at 60 m/s.A second string of 40% greater linear density has the same tension applied as in the first string.What will be the resulting wave speed in the second string?

A) also 60 m/s
B) 51 m/s
C) 72 m/s
D) 55 m/s

Question 17

The wave-related quantity algebraically equivalent to 1/f is:

A) ω
B) T
C) A
D) λ

Question 18

For a wave traveling in a string,by what factor would the tension need to be increased to triple the wave speed?

A) 2.7
B) 9.0
C) 3.0
D) 1.7

Question 19

A 2.0-m long piano string of mass 40 g is under a tension of 338 N.Find the speed with which a wave travels on this string.

A) 130 m/s
B) 260 m/s
C) 520 m/s
D) 1040 m/s

Question 20

If a radio wave has speed 3.00 × 10⁸ m/s and frequency 99.7 MHz,what is its wavelength?

A) 8.78 m
B) 1.50 m
C) 2.78 m
D) 3.01 m

Question 21

The lowest A on a piano has a frequency of 27.5 Hz.If the tension in the 2.0-m long string is 151 N and one-half wavelength occupies the string,what is the mass of the string?

A) 100 g
B) 25 g
C) 37 g
D) 50 g

Question 22

How many nodes does a standing wave in a string have at the frequency of the sixth harmonic?

A) 12
B) 6
C) 3
D) The answer is not given.

Question 23

The superposition principle has to do with which of the following?

A) effects of waves at great distances
B) the ability of some waves to move very far
C) how displacements of interacting waves add together
D) relativistic wave behavior

Question 24

A string with fixed ends is made to go into standing wave patterns.At a given tension,the lowest frequency for which such a pattern exists is 150 Hz.Which of the following frequencies would also cause a standing wave pattern in this case?

A) 250 Hz
B) 500 Hz
C) 750 Hz
D) All of the above frequencies will cause a standing wave pattern in this case.

Question 25

If I double the mass per unit length of guitar string,its natural frequency changes by what factor?

A) 2.0
B) 1.4
C) 1.0
D) 0.71

Question 26

Standing waves can result from _____ waves.

A) longitudinal
B) transverse
C) both longitudinal and transverse
D) neither longitudinal nor transverse

Question 27

Two water waves meet at the same point,one having a displacement above equilibrium of 60 cm and the other having a displacement above equilibrium of 40 cm.At this moment,what is the resulting displacement above equilibrium?

A) 140 cm
B) 100 cm
C) 70 cm
D) Information about the amplitudes needs to be given to find an answer.

Question 28

A standing wave is set up in a 2.0-m string fixed at both ends.The string vibrates in 3 distinct segments when driven by a 120-Hz source.In how many distinct standing wave segments will the string vibrate if the tension is increased by a factor of 4?

A) 3
B) 6
C) 9
D) No standing wave pattern occurs.

Question 29

A 1.5-m string is held fixed at both ends.When driven by a 180-Hz source,the string vibrates in 3 distinct segments.What is the natural fundamental frequency of the string?

A) 30 Hz
B) 60 Hz
C) 90 Hz
D) 540 Hz

Question 30

If a guitar string has a fundamental frequency of 250 Hz,what is the frequency of its third harmonic?

A) 250 Hz
B) 750 Hz
C) 1000 Hz
D) 1500 Hz

Question 31

A standing wave is set up in a 100-cm string fixed at both ends.The string vibrates in 5 distinct segments when driven by a 120-Hz source.What is the wavelength?

A) 10 cm
B) 20 cm
C) 40 cm
D) 80 cm

Question 32

A note is being played on a string on a guitar.The string is then pushed to the side while still in contact with the same fret.What happens to the frequency of the note then played compared to the original note?

A) It is the same note since the same fret is being used.
B) It is at higher frequency than the original note.
C) It is at lower frequency than the original note.
D) It can be either higher of lower frequency depending on whether the original note was above or below middle C.

Question 33

A string of length L with fixed ends is made to go into standing wave patterns.What is the longest wavelength associated with all possible standing wave patterns in this situation?

A) L/4
B) L/2
C) L
D) 2L

Question 34

What is the cause of refraction of a wave traveling from one medium to another?

A) There is a frequency change due to the change in the medium
B) There is a speed change due to the change in the medium.
C) There is a change in wave amplitude due to the change in the medium.
D) None of the above are associated with refraction.

Question 35

A radar pulse is bounced off the Moon at a distance of 400,000 km.What is the time from the transmitting of the pulse until its return?

A) 1.28 s
B) 2.56 s
C) 2.67 s
D) 3.84 s

Question 36

A 100-m long high-voltage cable is suspended between two towers.The mass of the 100-m cable is 200 kg.If the tension in the cable is 20,000 N,what is the lowest frequency at which this cable can oscillate?

A) 0.50 Hz
B) 0.61 Hz
C) 0.75 Hz
D) 1.5 Hz

Question 37

Tripling the tension in a guitar string will change its natural frequency by what factor?

A) 3
B) 3^1/2
C) 3^-1/2
D) 1.5

Question 38

A C note (f = 128 Hz)is sounded on a piano.If the length of the piano wire is 1.00 m and its mass density is 5.00 g/m,what is the tension in the wire?

A) 84 N
B) 328 N
C) 655 N
D) 1310 N

Question 39

If the tension on a guitar string is increased by a factor of 2,the fundamental frequency at which it vibrates is changed by what factor?

A) 0.5
B) 2^1/2
C) 2^-1/2
D) 2

Question 40

Equal wavelength waves of amplitude 0.25 m and 0.10 m interfere with one another.What is the resulting minimum amplitude that can result?

A) 0.15 m
B) 0.10 m
C) 0 m
D) -0.40 m