Unit 8 Test

Two waves arrive at the same place at the same time exactly out of step with each other (a crest hits a trough). Each wave has an amplitude of 2.5 m. The resulting wave has an amplitude of

0 m

The period of an ocean wave is 10 seconds. What is the wave's frequency?

0.1 Hz

A weight on the end of a spring bobs up and down one complete cycle every 4.0 seconds. Its frequency is

0.25 Hz

A 680-Hz sound wave travels at 340 m/s in air, with a wavelength of

0.5 m

A certain ocean wave has a frequency of 0.05 Hz and a wavelength of 10 meters. What is the wave's speed?

0.5 m/s

A certain ocean wave has a frequency of 0.07 Hz and a wavelength of 10 meters. What is the wave's speed?

0.70 m/s

The frequency of the second hand on a clock is

1/60 hertz

Compared to a sound of 10 dB, a sound of 50 dB has

10,000 times the intensity

One object makes a sound of 20 dB. A second object object makes a sound of 60 dB. How many times greater is the intensity of the sound wave?

10,000 x's

One sound wave produced a sound of 30 dB. Another produces a sound of 60 dB. How many times greater is its intensity?

1000 x's

Suppose you sound a 1054 Hz tuning fork at the same time you play a piano string. You hear 2 beats/second. You tighten the piano string very slightly and now hear 3 beats/second. What was the original frequency of the piano string?

1056 Hz

A 1134-Hz tuning fork is sounded at the same time a piano note is struck. You hear three beats per second. What is the frequency of the piano string?

1131 or 1137 (not enough information to determine)

A sound wave that has a wavelength of 2 m in room-temperature air has a frequency of about (The speed of sound in air is about 340 m/s)

170 Hz

The amplitude of a particular wave is 1 meter. The top-to-bottom distance of the disturbance is

2 m

The average human range of hearing is between

20 - 20,000 Hz

Sounds that are ultrasonic are sounds above

20,000 Hz

A skipper on a boat notices wave crests passing the anchor chain every five seconds. The skipper estimates the distance between the crests at 15 m. What is the speed of the water waves?

3 m/s

Beats are produced when two tuning forks, one of frequency 240 Hz and the other of frequency 246 Hz are sounded together. The frequency of the beats is

6 Hz

A cork floating in a pool oscillates up and down three complete cycles in 1 second as a wave passes by. The wave's wavelength is 2 meters. What is the wave's speed?

6 m/s

Beats are produced when two tuning forks, one of frequency 240 Hz and the other of frequency of 248 Hz are sounded together. The frequency of the beats is

8 Hz

The amplitude of a particular wave is 4.0 m. The top-to-bottom distance of the disturbance is

8.0 m

What happens when an airplane is flying faster than the speed of sound?

A shockwave is produced

Unlike a transverse wave, a longitudinal wave has no

Amplitude Frequency Wavelength Speed longitudinal wave has all of the above

Where can you touch a standing wave on a rope without disturbing the wave?

At a node

Frequency and Period are directly proportional to one another.

False

Sound waves transfer energy through the air to the eardrum

True

Sound waves cannot travel in

a vacuum

An example of a bow wave is

a wake behind a boat

Resonance occurs when

an object is forced to vibrate at its natural frequency

In a standing wave, the crests occur here

anti-node

The threshold of pain and where hearing damage can begin to occur is

around 100 dB

A periodic change in loudness caused by the interference of slightly differing frequencies

beats

Which of the following could result in hearing damage?

being exposed to a sound of 120 dB

Our brain will perceive a soundwave with a larger amplitude as

being louder

When crests or troughs overlap and the result is an increase in amplitude

constructive interference

The tallest point on a wave

crest

As the sound of a car's horn passes and recedes from you, the pitch of the horn seems to

decrease

Noise-canceling earphones are an example of

destructive interference

Sometimes there are "deadspots" in an auditorium because of

destructive interference of sound waves

The change in frequency of a wave due to the motion of the source or observer

doppler effect

The number of cycles in a given time period

frequency

What determines the pitch of a sound?

frequency

Two waves arrive at the same place at the same time exactly in step with each other. Each wave has an amplitude of 1 m. The resulting wave has an amplitude

greater than 1 m

An observer on the ground hears a sonic boom which is created by an airplane flying at a speed

greater than the speed of sound

Beats can be heard when two tuning forks

have almost the same frequency and are sounded together

The unit for frequency

hertz

Suppose a bug is jiggling up and down and swimming towards you at the same time. Compared to the frequency at which the bug is emitting waves, the frequency of the waves reaching you is

higher

Standing waves can be set up

in organ pipes by blowing across the top of a soda bottle on strings of musical instruments

Beats (in terms of sound) result from sound

interference

The phenomenon of beats results from sound

interference

When two or more waves are at the same place at the same time, the resulting effect is called

interference

If you are standing equally distant from two television sets that are emitting the exact same sound waves, the sound

is louder because the waves constructively interfere

A sonic boom

is swept continuously behind a plane flying faster than the speed of sound

A transverse wave is created on a slinky. If the frequency becomes greater, what happens to the wavelength?

it becomes shorter

A red-shift in stars indicates that stars are moving away from us because

light emitted has a different frequency than expected due to the doppler effect

A sound wave is a

longitudinal wave

A wave in which the motion of the medium is parallel to the wave motion

longitudinal wave

Sound is an example of a

longitudinal wave

Suppose a bug is jiggling up and down and swimming away from you at the same time. Compared to the frequency at which the bug is emitting waves, the frequency of the waves reaching you is

lower

When more holes are covered on a recorder, the frequency becomes

lower, because the wavelength is larger

Sound waves in air are a series of

molecules that move closer and further apart periodic compressions and rarefactions high and low pressure regions

An explosion occurs 34,000 m away. Given that sound travels at 340 m/s, the time it takes for the sound to reach you is

more than 20 s

Which of the following is not an example of the Doppler effect?

pendulum swinging

The time needed for a wave to make one complete cycle is its

period

the time for one cycle

period

A change in frequency of sound results in a change in ______ by our brain

pitch

A person rubs her finger around the edge of a wine glass and the wine glass starts to "sing". This is an example of

resonance

A singer shattering crystal glass with her voice is a demonstration of

resonance

Occurs when the frequency of forced vibrations matches natural frequency

resonance

The Tacoma Narrows Bridge collapsed due to

resonance

Occurs when the speed of a plane is greater than the speed of the sound wave

shock wave

You dip your finger repeatedly into water and make waves. If you dip your finger more frequently, the wavelength of the waves

shortens

A sound wave that has a higher frequency has a wavelength that is

shorter

Back and forth wave or vibratory motion

simple harmonic motion

Compared to the speed of light, sound travels

slower

In which one of the following does sound travel the fastest

solid

Which of the following is NOT a transverse wave?

sound

The Doppler effect applies to

sound waves water waves light waves radio waves

Infrasonic sounds are

sounds that are too low to hear.

An aircraft that flies slower than the speed of sound is said to be

subsonic

An aircraft that flies faster than the speed of sound is said to be

supersonic

The speed of a sound wave depends on

the air temperature

In a transverse wave, the wavelength is the distance from crest to crest. In a longitudinal wave, the wavelength is

the distance from the start of a compression to the start of the next compression

The period of a pendulum depends on

the length of the pendulum

The Doppler effect is the change in observed frequency due to

the motion of the source or observer

A pendulum bob is pulled back 10 degrees and released when it has 50 g on it. The period is measured. A second trial is done with a 100 g bob. Ignoring the effects of air resistance, the 100 g bob will have

the same period because period does not depend on mass.

A Doppler effect occurs when a source of sound moves

toward you away from you

A wave created by shaking a rope up and down is called a

transverse wave

A wave in which the motion of the medium is perpendicular to the wave motion

transverse wave

A dog whistle utilizes

ultrasonic sounds

Sound waves are produced by

vibrating objects

The source of all wave motion is

vibration

The distance between two successive points on a wave

wavelength