Question 1

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?

Accepted Answer

The answer of The lowest A on a piano has...

Question 2

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

Accepted Answer

The answer of How many nodes does a standing wave...

Question 3

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

Accepted Answer

The superposition principle states that when two waves interact, the resulting displacement at any given point is the sum of the displacements of the individual waves. This principle is the basis for wave interference and can help explain phenomena like diffraction and standing waves.

Question 4

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?

Accepted Answer

The answer of A string with fixed ends is made...

Question 5

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

Accepted Answer

According to the formula for the natural frequency of a string, which is given by f=(1/2L)*sqrt(T/U), where L is the length of the string, T is the tension in the string, and U is the linear density (mass per unit length) of the string, we can see that increasing the linear density of the string by a factor of two will decrease the natural frequency by a factor of sqrt(2), or approximately 0.71. Therefore, the correct answer is D.

Question 6

Standing waves can result from _____ waves.

Accepted Answer

Standing waves can result from both longitudinal and transverse waves, as they are a phenomenon of wave interference that can occur with any type of wave that reflects and interferes with itself.

Question 7

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?

Accepted Answer

The resulting displacement is the sum of the individual displacements: 60 cm + 40 cm = 100 cm.

Question 8

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?

Accepted Answer

The answer of A standing wave is set up in...

Question 9

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?

Accepted Answer

The string vibrates in 3 segments, indicating the third harmonic (n=3). The frequency of the third harmonic is 180 Hz. The fundamental frequency (first harmonic, n=1) is 180 Hz / 3 = 60 Hz.

Question 10

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

Accepted Answer

The frequency of the third harmonic is three times the fundamental frequency, so the frequency of the third harmonic is 3 * 250 Hz = 750 Hz.

Question 11

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?

Accepted Answer

The number of segments is equal to the number of nodes in the standing wave. In this case, there are 5 segments or nodes. 
The fundamental frequency of a standing wave in a string fixed at both ends is given by:
f = (n/2L) * sqrt(T/μ)
where n is the number of segments or nodes, L is the length of the string, T is the tension in the string, and μ is the linear density of the string. 
Solving for the wavelength, we get:
λ = 2L/n = 200/5 = 40 cm. 
Therefore, the wavelength is 40 cm.

Question 12

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?

Accepted Answer

Pushing the string to the side while in contact with the same fret increases the tension in the string, which increases the frequency of the vibration, resulting in a higher pitched note.

Question 13

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?

Accepted Answer

The answer of A string of length L with fixed...

Question 14

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

Accepted Answer

Refraction occurs because the speed of the wave changes when it travels from one medium to another. This change in speed causes the wave to bend, or refract. The frequency and amplitude of the wave remain unchanged during refraction.

Question 15

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?

Accepted Answer

The time taken for the pulse to travel to the Moon and back can be calculated using the formula: time = 2 x distance / speed of light.
Assuming a speed of light of 3 x 10^8 m/s, the distance of 400,000 km can be converted to meters by multiplying by 1000. Therefore, the distance is 4 x 10^8 m. 
Substituting the values in the formula, we get:
time = 2 x 4 x 10^8 / 3 x 10^8
time = 2.67 seconds
Hence, the answer is C) 2.67 s.

Question 16

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?

Accepted Answer

The lowest frequency at which the cable can oscillate is given by:f = (1/2π)√(T/m)where T is the tension in the cable and m is the mass of the cable.Substituting the given values, we get:f = (1/2π)√(20,000 N / 200 kg) = 0.50 Hz

Question 17

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

Accepted Answer

The natural frequency of a string is proportional to the square root of the tension. Tripling the tension increases the frequency by a factor of 3^1/2.

Question 18

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?

Accepted Answer

The formula for the tension in a string is T = (mu)f^2L, where mu is the mass density, f is the frequency, and L is the length of the string. 
Plugging in the given values: 
T = (0.005 kg/m)(128 Hz)^2(1.00 m) 
T = 328 N

Therefore, the correct choice is B.

Question 19

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?

Accepted Answer

The fundamental frequency of a string is proportional to the square root of the tension. If the tension is increased by a factor of 2, the frequency increases by a factor of 2^1/2.

Question 20

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?

Accepted Answer

The minimum amplitude occurs when the waves interfere destructively, which is the difference in their amplitudes: 0.25 m - 0.10 m = 0.15 m.

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