Question 1

A sound wave in air is classified as which type of wave, and what is the main direction of particle motion relative to wave propagation?

Accepted Answer

Longitudinal wave; particles move parallel to wave direction

Question 2

A guitar string is fingered so that its vibrating length is halved. If the original fundamental frequency was $$f_1$$, what is the new fundamental frequency, assuming the wave speed remains constant?

Accepted Answer

$$2f_1$$

Question 3

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

Accepted Answer

The displacement at a point is the sum of the displacements of all waves present

Question 4

A tube open at both ends has a length $$L. $$What is the wavelength of the fundamental mode?

Accepted Answer

$$\$$lambda_1$$ = 2L$$

Question 5

For a string fixed at both ends, the frequency of the $$mth $$mode is given by which formula?

Accepted Answer

$$f_m = m f_1$

Question 6

A tube closed at one end and open at the other has a length $$L. $$What is the wavelength of the fundamental mode?

Accepted Answer

$$\$$lambda_1$$ = 4L$$

Question 7

At room temperature ($$20^\circC$$), what is the approximate speed of sound in air?

Accepted Answer

$$343\ \mathrm{m/s}$$

Question 8

Which of the following statements about standing waves is correct?

Accepted Answer

Standing waves occur only when the length of the medium matches the frequency of the wave

Question 9

A flute can be modeled as a tube open at both ends. If the tube is $$0.68\ \mathrm{m}$$ long and the speed of sound is $$340\ \mathrm{m/s}$$, what is the fundamental frequency?

Accepted Answer

$$500\ \mathrm{Hz}$$

Question 10

Which of the following is true about the harmonic series for a tube closed at one end and open at the other?

Accepted Answer

Only odd harmonics are present

Question 11

A string fixed at both ends has a length $$L$$ and wave speed $$v. $$What is the frequency of the second harmonic?

Accepted Answer

$$f_2 = v / L$

Question 12

If the tension in a guitar string is quadrupled, how does the speed of the wave on the string change?

Accepted Answer

It doubles

Question 13

Which formula gives the speed of sound in air as a function of temperature $$T_C in $$degrees Celsius?

Accepted Answer

$$v = 331 + \frac{3}{5} T_C$$

Question 14

A tube closed at one end and open at the other is $$0.5\ \mathrm{m}$$ long. What is the fundamental frequency if the speed of sound is $$340\ \mathrm{m/s}$$?

Accepted Answer

$$f_1$$ = \frac{v}{4L} = \frac{340}{2} = 170\ \mathrm{Hz}$$

Question 15

Which of the following best describes a node in a standing wave?

Accepted Answer

A point of zero displacement

Question 16

A musician tunes a string by increasing its tension. What effect does this have on the fundamental frequency?

Accepted Answer

The fundamental frequency increases

Question 17

Which equation correctly relates the frequency, wavelength, and speed of a wave?

Accepted Answer

$$v = f \lambda$$

Question 18

A tube open at both ends and a string fixed at both ends have the same length $$L$$ and wave speed $$v. $$Which has the same harmonic series and fundamental frequency formula?

Accepted Answer

Both have a full harmonic series and $$f_1 = v / 2L$

Question 19

A sound wave travels $$3\ \mathrm{km} in $$air. Approximately how long does it take to reach your ear?

Accepted Answer

$$3\ \mathrm{s}$$

Question 20

Which of the following is true about air as a medium for sound waves?

Accepted Answer

Air is a non-dispersive medium; all frequencies travel at the same speed

Waves and Sound: Properties, Reflection, Superposition, Standing Waves, and Applications in Strings and Tubes

Study Guide - Practice Questions

Study Guide - Flashcards