Q: A periodic wave has a frequency of 500 Hz and a wavelength of 0.68 m. What is its speed?

$$v = f \lambda = 500 \times 0.68 = 340 m/s$$

Question 1

Which of the following best describes a transverse wave?

Accepted Answer

The displacement of the medium is perpendicular to the direction of wave propagation.

Question 2

A guitar string is tightened, increasing its tension. What effect does this have on the speed of a wave traveling along the string?

Accepted Answer

The wave speed increases because the tension increases.

Question 3

Which equation correctly relates the speed $$v$$, frequency $$f$$, and wavelength $$\lambda of a $$wave?

Accepted Answer

$$v = f \lambda$$

Question 4

A sound wave travels through air and then enters water. What happens to its speed and wavelength, assuming frequency remains constant?

Accepted Answer

Speed increases and wavelength increases.

Question 5

The period $$T of a $$simple pendulum of length $$L is $$given by which formula?

Accepted Answer

$$T = 2\pi \sqrt{\frac{L}{g}}$$

Question 6

A speaker emits sound uniformly in all directions with a power output of $$P = 50 W. $$What is the intensity $$I at a $$distance $$r = 5 m $$from the speaker?

Accepted Answer

$$I = \frac{P}{4\pi r^2$} = \frac{50}{4\pi (5)^2$}$$

Question 7

If the intensity of a sound increases by a factor of 100, by how many decibels does the sound intensity level increase?

Accepted Answer

20 dB

Question 8

Which of the following is true about longitudinal waves?

Accepted Answer

The displacement of the medium is parallel to the direction of wave propagation.

Question 9

A student in a small room measures a sound intensity level of 60 dB. If eight identical sources are added, all producing the same intensity, what is the new sound intensity level?

Accepted Answer

69 dB

Question 10

The mechanical energy $$E of a $$mass-spring system in simple harmonic motion is given by:

Accepted Answer

$$E = \frac{1}{2}mv^2$ + \frac{1}{2}kx^2$

Question 11

A periodic wave has a frequency of 500 Hz and a wavelength of 0.68 m. What is its speed?

Accepted Answer

$$v = f \lambda = 500 	imes 0.68 = 340 m/s$$

Question 12

Which property of a wave determines its pitch as perceived by the human ear?

Accepted Answer

Frequency

Question 13

A wave on a string has a mass per unit length $$\mu = 0.01 kg/m $$and tension $$T = 100 N. $$What is the speed of the wave?

Accepted Answer

$$v = \sqrt{\frac{T}{\mu}} = \sqrt{\frac{100}{0.01}} = 100 m/s$$

Question 14

If the amplitude of a sound wave doubles, what happens to the intensity?

Accepted Answer

Intensity increases by a factor of 4.

Question 15

A pendulum has a length of 2 m. What is its period? (Use $$g = 9.8 m/s$^2)$$

Accepted Answer

$$T = 2\pi \sqrt{\frac{2}{9.8}} \approx 2.84 s$$

Question 16

The sound intensity level $$\beta in $$decibels is given by:

Accepted Answer

$$\beta = (10 \ \mathrm{dB}) \log_{10} \left( \frac{I}{I_0$} \right)$$

Question 17

A wave on a string has a frequency of 120 Hz and a speed of 60 m/s. What is its wavelength?

Accepted Answer

$$\lambda = \frac{v}{f} = \frac{60}{120} = 0.5 m$$

Question 18

Which of the following statements about wave speed is correct?

Accepted Answer

Wave speed depends on the properties of the medium.

Question 19

A sound source emits a spherical wave with intensity $$I = 120 W/m$^2 at a $$distance of 4 m. What is the power $$P of $$the source?

Accepted Answer

$$P = I 	imes 4\pi r^2$ = 120 	imes 4\pi 	imes 16 = 7,680\pi W$$

Waves and Sound: Study Notes for Phys1310 Exam 2

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드