Sound Wave Physics Review

Flashcards covering sound wave physics, including properties, behavior, and related concepts.

Which of the following is a false statement about sound waves?

Sound can travel through a vacuum.

In general, through which medium does sound conduct fastest?

Solids

What is the approximate speed of sound in a steel rod?

5000 m/s

As the temperature of the air increases, what happens to the velocity of sound, assuming other factors remain constant?

It increases.

How does doubling the frequency of a sound wave affect its velocity through the air?

The velocity remains the same.

Compared to the wavelength of a 400 Hz sound, what is the wavelength of a 200 Hz sound in air?

Twice as long

What term is used for sound vibrations with frequencies greater than 20,000 Hz?

Ultrasonics

What term is used for sound vibrations with frequencies less than 20 Hz?

Infrasonics

If you move to a point twice as far away from a sound source emitting waves uniformly, what happens to the frequency of the sound?

The frequency remains unchanged.

For spherically diverging waves, intensity is proportional to what?

1/R^2

If the intensity of a point source at distance d is I, what is the intensity at a distance 2d?

I/4

You double your distance from a sound source radiating equally. What happens to the intensity of the sound?

It reduces to one-fourth its original value.

You double your distance from a sound source radiating equally. What happens to the intensity level of the sound?

It drops by 6 dB.

Which of the following increases as a sound becomes louder?

Amplitude

You move slowly toward a speaker emitting a pure tone. What characteristic of the sound increases?

Amplitude

What determines the 'loudness' of a musical note?

Amplitude

What determines the 'pitch' of a musical note?

Frequency

When sound passes from air into water, which property does not change?

Frequency

How are pressure and displacement waves related in terms of phase?

90° out of phase.

What do the standing wave on a guitar string and the sound wave generated by the guitar have in common?

They have the same frequency.

In a resonating pipe which is open at both ends, what exists at each end?

Displacement antinodes

Consider an open pipe of length L. What are the wavelengths of the three lowest tones produced by this pipe?

2L, L, 2L/3

The lowest tone to resonate in an open pipe is 200 Hz. Which one of the following frequencies will not resonate in the same pipe?

900 Hz

An open pipe of length L is resonating at its fundamental frequency. Which statement is correct?

1. The wavelength is 2L and there is a displacement node at the pipe's midpoint.

In a resonating pipe which is open at one end and closed at the other, there

1. is a displacement node at the closed end and a displacement antinode at the open end.

Consider a closed pipe of length L. What are the wavelengths of the three lowest tones produced by this pipe?

4L, 4L/3, 4L/5