26 terms

physics exam 2 sound

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What is the speed of sound in air?
(at room temperature)
340 m/s
A piano tuner knows that a key on the piano is tuned to the frequency of his tuning fork when he strikes them at the same time and the number of beats he hears each second is

a) 1
b) 3
c) 2
d) 4
e) 0
e
A general rule for estimating the distance in kilometers between an observer and a lightning bolt is to count the number of seconds between seeing the lightning and hearing it, and dividing by

a) 5
b) 3
c) 2
d) 4
e) none of these
b
The beat frequency produced when a 240 hertz tuning fork and a 246 hertz tuning fork are sounded together is

a) 245 hertz
b) 240 hertz
c) 12 hertz
d) 6 hertz
e) none of the above
d
Inhaling helium increases the pitch of your voice. One reason for this is that sound travels

a) faster in helium than in air
b) slower in helium than in air
c) the same speed in helium, but the wavelength is greater
a
Resonance can be looked at as forced vibration with the

a) matching of wave amplitudes
b) minimum beat frequency
c) maximum amount of energy input
d) matching of constructive and destructive interference
e) least amount of energy input
e
When the handle of a tuning fork is held solidly against a table, the sound becomes louder and the time that the fork keeps vibrating

a) remains the same
b) becomes shorter
c) becomes longer
b
A 340-hertz sound wave travels at 340 m/s in air with a wavelength of

a) 1 m
b) 1000 m
c) 10 m
d) 100 m
e) none of the above
a
For AM radio, the A stands for

a) agony
b) authorized
c) acceleration
d) almost
e) amplitude
e
Which doesn't belong to the same family?

b) ultrasonic waves
c) longitudinal waves
d) shock waves
e) infrasonic waves
a
Sound waves can interfere with one another so that no sound results.

a) true
b) false
c) either true or false, depending on the air temperature
a
Caruso is said to have made a crystal chandelier shatter with his voice. This is a demonstration of

a) interference
b) an echo
c) sound refraction
d) resonance
e) beats
d
The object with the highest natural frequency is a

a) large bell
b) small bell
c) medium sized bell
b
The energy of sound in air eventually becomes

a) cancelled by destructive interference
b) cancelled by both destructive and constructive interference
c) increased internal energy of the air
d) weaker and weaker until it disappears
c
When the speed of sound near the ground is greater than it is at higher altitudes, the sound tends to be bent

a) to the right
b) upward
c) downward
d) to the left
e) none of the above
b
sound travels faster in

a) water
b) a vacuum
c) steel
d) air
e) sound travels at about the same speed in all of the above media
c
The approximate range of human hearing is

a) 10 hertz to 10,000 hertz
b) 20 hertz to 20,000 hertz
c) 40 hertz to 40,000 hertz
d) actually all of these
b
The source of every sound is something that is

a) vibrating
b) undergoing simple harmonic motion
c) a net emitter of energy
d) accelerating
e) moving
a
Double the frequency of sound and you also double its

a) speed
b) wavelength
c) amplitude
d) all of these
e) none of these
e
We are best at hearing

a) both infrasonic and ultrasonic sounds
b) ultrasonic sound
c) infrasonic sound
d) none of the above
d
The speed of a sound wave in air depends on

a) the air temperature
b) its frequency
c) its wavelength
d) all of the above
e) none of the above
a
The explanation for refraction must involve a change in

a) frequency
b) wavelength
c) speed
d) all of the above
e) none of the above
c
The frequencies of sound that carry farther in air are

a) ultrasonic
b) low
c) high
b
The wavelengths of sound that carry farther in air are relatively

a) long
b) short
c) ultrasonic
a
Longitudinal waves of different lengths are traveling though a long metal rod. Those that travel at the greatest speed are

a) those of medium length
b) the shortest
c) the longest
d) impossible to predict without knowing the type of metal
e) none of the above
e
Suppose you sound a 1056-hertz tuning fork at the same time you strike a note on the piano and hear 2 beats/second. You tighten the piano string very slightly and now hear 3 beats/second. What is the frequency of the piano string?

a) 1058 hertz
b) 1054 hertz
c) 1053 hertz
d) 1059 hertz
e) 1056 hertz
d