Q: A wave has a frequency of 500 Hz and a wavelength of 0.7 m. What is its speed?

$$v = 500 \times 0.7 = 350\ \mathrm{m/s}$$

Question 1

Which of the following best describes a transverse wave?

Accepted Answer

A wave in which the displacement is perpendicular to the direction of wave travel.

Question 2

A wave pulse travels along a stretched string. If the tension in the string is quadrupled, what happens to the speed of the wave?

Accepted Answer

It doubles.

Question 3

The speed of a wave on a string is given by $$v = \sqrt{\frac{T_s}{\mu}}. If $$the mass per unit length $$\mu is $$doubled while keeping the tension $$T_s$$ constant, what happens to the wave speed?

Accepted Answer

It decreases by a factor of $$\sqrt{2}.$$

Question 4

A sinusoidal wave is described by $$D(x, t) = A \sin(kx - \omega t + \$$phi_0$$). $$What does the parameter $$A$$ represent?

Accepted Answer

The amplitude of the wave.

Question 5

A sound wave travels from air into water. Which of the following quantities remains unchanged?

Accepted Answer

Frequency

Question 6

A string of length 2.0 m and mass 10 g is under a tension of 80 N. What is the speed of a wave on this string?

Accepted Answer

$$v = \sqrt{\frac{80}{0.005}} = 126.5\ \mathrm{m/s}$$

Question 7

A wave has a frequency of 500 Hz and a wavelength of 0.7 m. What is its speed?

Accepted Answer

$$v = 500 	imes 0.7 = 350\ \mathrm{m/s}$$

Question 8

Which of the following statements about the amplitude of a wave on a string is correct?

Accepted Answer

Amplitude does not affect the wave speed.

Question 9

A sinusoidal wave on a string is described by $$y(x, t) = 0.02 \sin(8.96x - 3140t). $$What is the wavelength of the wave?

Accepted Answer

$$\lambda = \frac{2\pi}{8.96} = 0.70\ \mathrm{m}$$

Question 10

A light wave travels from air ($$n=1.0) $$into glass ($$n=1.5). If $$its wavelength in air is 600 nm, what is its wavelength in glass?

Accepted Answer

$$\lambda_{glass} = \frac{600}{1.5} = 400\ \mathrm{nm}$$

Question 11

The intensity of a spherical sound wave at a distance $$r_1 is$$ $$I_1. $$What is the intensity at a distance $$r_2 = 2r_1$?

Accepted Answer

$$I_2$$ = \frac{$$I_1$$}{4}$$

Question 12

A listener moves toward a stationary sound source with speed $$v_L. $$The frequency heard by the listener is given by:

Accepted Answer

$$f_L = f_S \left(\frac{v + v_L}{v}\right)$$

Question 13

A sinusoidal wave on a string has amplitude $$A$$, angular frequency $$\omega$$, and wave number $$k. $$What is the maximum transverse velocity of a point on the string?

Accepted Answer

$$v_{max} = \omega A$$

Question 14

The sound intensity level from one solo flute is 75 dB. If 10 flutists play together, what is the resulting sound intensity level?

Accepted Answer

80 dB

Question 15

A wave pulse travels along a string at speed $$v_0. If $$the string is replaced by one with three times the radius (same material, same tension), what is the new wave speed?

Accepted Answer

$$v = \frac{v_0$}{\sqrt{3}}$$

Question 16

A sinusoidal wave is described by $$y(x, t) = 0.05 \sin(4\pi x - 200\pi t). $$What is the period $$T of $$the wave?

Accepted Answer

$$T = \frac{2\pi}{200\pi} = 0.01\ \mathrm{s}$$

Question 17

The phase difference $$\Delta \phi$$ between two points separated by $$\Delta x on a $$wave with wavelength $$\lambda is$$:

Accepted Answer

$$\Delta \phi = 2\pi \frac{\Delta x}{\lambda}$$

Question 18

A sinusoidal wave on a string has displacement $$y(x, t) = A \sin(kx - \omega t). $$What is the acceleration of a point on the string?

Accepted Answer

$$a_y = -\$$omega^2$$ A \sin(kx - \omega t)$$

Traveling Waves: Properties, Mathematics, and Applications

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