Chapter 19

Vibrations and Waves

A wiggle in time is a

a. vibration.

b. wave.

c. Both of these.

d. None of these.

A wiggle in time is a

a. vibration.

b. wave.

c. Both of these.

d. None of these.

A wave is a vibration in

a. space.

b. time.

c. Both of these.

d. None of these.

A wave is a vibration in

a. space.

b. time.

c. Both of these.

d. None of these.

When we consider how frequently a pendulum swings to and fro, we’re

talking about its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

When we consider how frequently a pendulum swings to and fro, we’re

talking about its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

When we consider the time it takes for a pendulum to swing to and fro, we’re

talking about the pendulum’s

a. frequency.

b. period.

c. wavelength.

d. amplitude.

When we consider the time it takes for a pendulum to swing to and fro, we’re

talking about the pendulum’s

a. frequency.

b. period.

c. wavelength.

d. amplitude.

When we consider how far a pendulum swings to and fro, we’re

talking about the pendulum’s

a. frequency.

b. period.

c. wavelength.

d. amplitude.

When we consider how far a pendulum swings to and fro, we’re

talking about the pendulum’s

a. frequency.

b. period.

c. wavelength.

d. amplitude.

The frequency of a wave is the inverse of its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

The frequency of a wave is the inverse of its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

Explanation: Note the inverse relationship: f = 1/T, T = 1/f.

If the frequency of a particular wave is 20 Hz, its period is

a. 1/20 second.

b. 20 seconds.

c. more than 20 seconds.

d. None of the above.

If the frequency of a particular wave is 20 Hz, its period is

a. 1/20 second.

b. 20 seconds.

c. more than 20 seconds.

d. None of the above.

Explanation: Note when f = 20 Hz, T = 1/f = 1/20 Hz = 1/20 second.

In Europe an electric razor completes 50 vibrations in 1 second. The frequency of these vibrations is

a. 50 Hz with a period of 1/50 second.

b. 1/50 Hz with a period of 50 seconds.

c. 50 Hz with a period of 50 seconds.

d. 1/50 Hz with a period of 1/50 second.

In Europe an electric razor completes 50 vibrations in 1 second. The frequency of these vibrations is

a. 50 Hz with a period of 1/50 second.

b. 1/50 Hz with a period of 50 seconds.

c. 50 Hz with a period of 50 seconds.

d. 1/50 Hz with a period of 1/50 second.

Explanation: Note when f = 50 Hz, T = 1/f = 1/50 Hz = 1/50 second.

For a transverse wave, the distance between adjacent peaks in the direction

of travel is its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

For a transverse wave, the distance between adjacent peaks in the direction

of travel is its

a. frequency.

b. period.

c. wavelength.

d. amplitude.

Explanation: The wavelength of a transverse wave is also the distance between adjacent troughs, or between any adjacent identical parts of the waveform.

If you dip your finger repeatedly onto the surface of still water, you produce waves.

The more frequently you dip your finger, the

a. lower the wave frequency and the longer the wavelengths.

b. higher the wave frequency and the shorter the wavelengths.

c. Strangely, both of these.

d. None of these.

If you dip your finger repeatedly onto the surface of still water, you produce waves.

The more frequently you dip your finger, the

a. lower the wave frequency and the longer the wavelengths.

b. higher the wave frequency and the shorter the wavelengths.

c. Strangely, both of these.

d. None of these.

Explanation: Strange indeed, if you seriously answered c.!

The speed of a wave can be found by multiplying its frequency by the

a. period.

b. wavelength.

c. amplitude.

d. None of the above.

The speed of a wave can be found by multiplying its frequency by the

a. period.

b. wavelength.

c. amplitude.

d. None of the above.

The vibrations along a transverse wave move in a direction

a. along the wave.

b. perpendicular to the wave.

c. Both of these.

d. None of these.

The vibrations along a transverse wave move in a direction

a. along the wave.

b. perpendicular to the wave.

c. Both of these.

d. None of these.

The vibrations along a longitudinal wave move in a direction

a. along the wave.

b. perpendicular to the wave.

c. Both of these.

d. None of these.

The vibrations along a longitudinal wave move in a direction

a. along the wave.

b. perpendicular to the wave.

c. Both of these.

d. None of these.

A common example of a longitudinal wave is

a. sound.

b. light.

c. Both of these.

d. None of these.

A common example of a longitudinal wave is

a. sound.

b. light.

c. Both of these.

d. None of these.

Wave interference occurs for

a. water waves.

b. sound waves.

c. light waves.

d. All of these.

Wave interference occurs for

a. water waves.

b. sound waves.

c. light waves.

d. All of these.

A standing wave is produced by reflected waves undergoing

a. changes in frequency.

b. changes in amplitude.

c. interference.

d. Doppler shifts.

A standing wave is produced by reflected waves undergoing

a. changes in frequency.

b. changes in amplitude.

c. interference.

d. Doppler shifts.

The Doppler effect is characteristic of

a. sound waves.

b. light waves.

c. Both of these.

d. None of these.

The Doppler effect is characteristic of

a. sound waves.

b. light waves.

c. Both of these.

d. None of these.

The Doppler effect is concerned with changes in wave

a. frequency.

b. speed.

c. Both of these.

d. None of these.

The Doppler effect is concerned with changes in wave

a. frequency.

b. speed.

c. Both of these.

d. None of these.

Explanation: A common misconception is that the Doppler effect is a perceived change in speed—not so! Distinguish between speed (how fast) and frequency (how frequently)!

A shock wave is the result of wave

a. interference.

b. superposition.

c. amplification.

d. transference.

A shock wave is the result of wave

a. interference.

b. superposition.

c. amplification.

d. transference.

A sonic boom cannot be produced by

a. an aircraft flying slower than the speed of sound.

b. a whip.

c. a speeding bullet.

d. All of these.

A sonic boom cannot be produced by

a. an aircraft flying slower than the speed of sound.

b. a whip.

c. a speeding bullet.

d. All of these.

Comment: None of these produces a shock wave and a resulting sonic boom.