Test: Sound

Of the following materials, sound waves travel fastest through

• helium at 0°C.

• air at 0°C.

• copper at 0°C.

• air at 100°C.

The point at which a ray crosses a wave front corresponds to a ____ of a sound wave.

• wavelength

• compression

• trough

• source

A train moves down the track toward an observer. The sound from the train, as heard by the observer, is ___ the sound heard by a passenger on the train.

• the same as

• a different timbre than

• higher in pitch than

• lower in pitch than

At a distance of 3 m, the intensity of a sound will be ________ the intensity it was at a distance of 1 m.

• one-ninth

• one-third

• 3 times

• 9 times

The intensity of a sound at any distance from the source is directly proportional to the sound’s

• wavelength.

• pitch.

• power.

• frequency.

If the intensity of a sound is increased by a factor of 100, the new decibel level will increase

• by two units

• to twice the old one.

• by a factor of 10.

• by 20 units.

For a standing wave in an air column in a pipe that is open at both ends, there must be at least

• one node and one antinode

• two nodes and one antinode.

• two antinodes and one node.

• two nodes and two antinodes.

If a guitar string has a fundamental frequency of 500 Hz, what is the frequency of its second harmonic?

• 250 Hz

• 750 Hz

• 1000 Hz

• 2000 Hz

How many beats per second are heard when two vibrating tuning forks having frequencies of 342 Hz and 345 Hz are held side by side?

• 687 Hz

• 343.5 Hz

• 5 Hz

• 3 Hz

In the figure shown, a beat occurs at

• t₁.

• t₂.

• t₃.

• t₁ and t₃.