Question 1

A water droplet falls into a still pond, creating circular ripples as shown in the image. Which statement best describes the type of wave and the direction of energy transfer?

Accepted Answer

The ripples are transverse waves, and energy is transferred outward from the point of impact.

Question 2

In the context of a transverse wave on a string, as shown in the second image, which of the following best describes the motion of the particles in the string?

Accepted Answer

The particles move perpendicular to the direction of wave propagation.

Question 3

A pulse is generated by displacing one block in a spring-mass system (third image). What property allows the pulse to propagate through the system?

Accepted Answer

The elasticity of the medium, which allows energy to be transferred from one block to the next.

Question 4

A wave on a string is described by $$y(x, t) = 0.05 \cos(4\pi x - 200\pi t)$$, where $$x$$ and $$y$$ are in meters and $$t in $$seconds. What is the wavelength of this wave?

Accepted Answer

$$0.5\ \mathrm{m}$$

Question 5

A string under tension $$F$$ and with mass per unit length $$\mu$$ supports a wave. What is the correct formula for the speed of the wave on the string?

Accepted Answer

$$v = \sqrt{F/\mu}$$

Question 6

A sound wave travels through air at standard conditions ($$p = 101\ \mathrm{kN/m^2$}$$, $$\rho = 1.20\ \mathrm{kg/m^3$}). $$What is the speed of sound in air under these conditions?

Accepted Answer

$$v = \sqrt{\gamma p / \rho}$$,\ where\ \gamma = 1.4$

Question 7

A wave has a frequency of $$5\ \mathrm{Hz}$$ and a wavelength of $$2\ \mathrm{m}. $$What is its speed?

Accepted Answer

$$v = 10\ \mathrm{m/s}$$

Question 8

If the intensity of a sound at a certain distance is $$I$$, what will the intensity be if the distance from the source is doubled?

Accepted Answer

$$I/4$$

Question 9

A tuning fork produces a sound wave with an intensity level of $$80\ \mathrm{dB}. If $$the intensity is reduced by a factor of 100, what is the new intensity level?

Accepted Answer

$$60\ \mathrm{dB}$$

Question 10

A wave pulse travels from a thin string to a thick string. What happens to the reflected and transmitted pulses?

Accepted Answer

The reflected pulse is inverted, and the transmitted pulse is right-side up.

Question 11

Two identical waves traveling in opposite directions on a string interfere. What type of wave pattern is formed?

Accepted Answer

A standing wave

Question 12

A pipe open at both ends has a fundamental frequency $$f_0. If $$the pipe is cut in half, what is the new fundamental frequency?

Accepted Answer

$$2f_0$$

Question 13

A fire truck's siren emits a frequency $$f_s = 1380\ \mathrm{Hz} at $$rest. If a stationary observer hears the frequency as $$f_r = 1600\ \mathrm{Hz} as $$the truck approaches, what is the correct formula to find the speed of the truck?

Accepted Answer

$$v_s = v \left(\frac{f_r}{f_s} - 1\right) / \left(\frac{f_r}{f_s}\right)$$

Question 14

Which of the following best describes the principle of superposition for waves?

Accepted Answer

The net displacement at any point is the sum of the displacements due to each wave.

Question 15

A string fixed at both ends vibrates at its fundamental frequency. If the length of the string is $$L$$ and the wave speed is $$v$$, what is the fundamental frequency?

Accepted Answer

$$f_1$$ = \frac{v}{2L}$$

Question 16

A sound wave in air has a frequency of $$500\ \mathrm{Hz}$$ and a wavelength of $$0.68\ \mathrm{m}. $$What is the speed of sound in air?

Accepted Answer

$$340\ \mathrm{m/s}$$

Question 17

If two sound waves of frequencies $$f_1 = 256$$\ \mathrm{Hz}$$ and f_2$ = 260\ \mathrm{Hz}$$ are played together, what is the beat frequency heard?

Accepted Answer

$$4\ \mathrm{Hz}$$

Question 18

A standing wave is formed on a string of length $$L$$ fixed at both ends. What is the wavelength of the second harmonic?

Accepted Answer

$$\$$lambda_2$$ = L$$

Wave Motion, Sound, and Interference: Physics with Calculus Study Notes

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