Physics B Questions And Answers Latest Top Score.
UNIT 1 - correct answer. LESSON 1
A decibel is a measure of ______________. - correct answer. sound intensity
The Doppler effect is a perceived change in frequency due to _____________________________. - correct answer. the...
A decibel is a measure of ______________. - correct answer. sound intensity
The Doppler effect is a perceived change in frequency due to
_____________________________. - correct answer. the relative motion of source
with respect to an observer
Which of the following wave characteristics is responsible for breaking the glass? -
correct answer. frequency
The compression of air in a sound wave corresponds to the ____ of a sine wave. -
correct answer. crest
Whales use _______sounds to communicate. - correct answer. infrasonic
Though sound is not a sine wave, it can have a particular frequency. Frequency of
sound waves is perceived by humans as _________________ . - correct answer.
pitch
When a heavy object is dropped into the sea, observers in the sea will hear it much
sooner than observers in the air, if they are at the same distance away. - correct
answer. True
When a sound wave originates in the air, the wave front traveling away from the source
has the shape of a ______________ . - correct answer. sphere
The siren of an ambulance will sound _____ in pitch to an observer in front of the
ambulance than it will to one who is behind the moving ambulance. - correct answer.
higher
,As a dolphin swims toward a fish, the dolphin sends out sound waves to determine the
direction the fish is moving. If the frequency of the reflected waves is higher than that of
the emitted waves, is the dolphin catching up to the fish or falling behind? - correct
answer. catching up
Dolphins pinpoint the location of fish by emitting sound waves and listening for the
reflection from the fish. Would dolphins be able to echolocate flying birds the same
way? - correct answer. No, because the speed of sound in air is much slower than in
water, so that the birds would seem much farther away.
An area of low pressure and low molecular density in a sound wave in air is called a(n)
___________ . - correct answer. rarefaction
The SI unit for intensity is watts/square meter. According to the equation for the intensity
of a spherical wave, the units of power should be in ___________. - correct answer.
watts
Speeches broadcast at intensities greater than 0.01 watts/square meter, but less than
1.0 watts per square meter, __________________ . - correct answer. could not be
understood by the listeners
According to its decibel level, a lawnmower is about __________as loud as a whisper. -
correct answer. four times
An object will resonate when exposed to sound waves at __________ . - correct
answer. its fundamental frequency
The organ directly responsible for turning vibrations into nerve impulses is the ______ .
- correct answer. cochlea
The unit for perceived loudness is the _____________ . - correct answer. decibel
When a guitar string is exposed to sound waves at its fundamental frequency, the guitar
string will ______________ . - correct answer. resonate
Anne attends a concert where she stands 10.0 m from the electric bass's amplifier.
What is the intensity of the sound waves received by Anne if the power otuput of the
amplifier is 150.0 W? - correct answer. 0.119 W/m^2
The intensity of a sound at any distance from the source is directly proportional to the
sound's - correct answer. power.
Sound waves - correct answer. are longitudinal waves.
Pitch depends on the ____ of a sound wave. - correct answer. frequency
,The Tacoma Narrows bridge collapsed in 1940 when winds caused ____ to build up in
the bridge. - correct answer. a standing wave
At a long distance from the source, spherical wave fronts can be treated as
____________________ waves. - correct answer. plane
At a large distance from a sound source, spherical wave fronts are viewed as - correct
answer. plane waves.
When the frequency of a force applied to a system matches the natural frequency of
vibration of the system, ____ occurs. - correct answer. resonance
If you are on a train, how will the pitch of the train's whistle sound to you as the train
moves? - correct answer. The pitch will not change.
The perceived loudness of a sound is measured in - correct answer. decibels
A sound twice the intensity of the faintest audible sound is not perceived as twice as
loud because the sensation of loudness in human hearing - correct answer. is
approximately logarithmic.
What are the units used to express the intensity of a sound? - correct answer. watts
per square meter
If the intensity of a sound is increased by a factor of 100, the new decibel level will
increase - correct answer. by 20 units.
The distance between wave fronts of plane waves corresponds to ____ of a sound
wave. - correct answer. one wavelength
The highness or lowness of a sound is perceived as - correct answer. pitch
Which of the following is the region of a sound wave in which the density and pressure
are greater than normal? - correct answer. compression
Of the following materials, sound waves travel fastest through - correct answer.
copper at 0°C.
The Doppler effect occurs with - correct answer. all waves
In general, sound travels faster through - correct answer. solids than through gases
The point at which a ray crosses a wave front corresponds to a ____ of a sound wave. -
correct answer. compression
, The property of sound called intensity is proportional to the rate at which energy flows
through - correct answer. an area perpendicular to the direction of propagation.
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. - correct answer.
higher in pitch than
The trough of the sine curve used to represent a sound wave corresponds to - correct
answer. a rarefaction.
The region of a sound wave in which air molecules are pushed closer together is called
a(n) ____________________. - correct answer. compression
Which of the following decibel levels is nearest to the value that you would expect for a
running vacuum cleaner? - correct answer. 70 dB
At a distance of 3 m, the intensity of a sound will be ____ the intensity it was at a
distance of 1 m. - correct answer. one-ninth
UNIT 1 - correct answer. LESSON 2
Which of the following would be the harmonic series for the fundamental frequency, f ? -
correct answer. f, 2 f , 3 f , 4 f , 5 f. ...
The sound quality of an instrument is often called its _____. - correct answer. timbre
An instrument for viewing the wave nature of sound is the ______________. - correct
answer. oscilloscope
For a harmonic series produced by a pipe closed at one end, the series will lack
_______. - correct answer. the even multiples of the fundamental frequency
The sound wave produced by a vibrating string is composed solely of the standing wave
of the fundamental frequency. - correct answer. False
The wavelength of the third harmonic of a guitar string that is 1.0 meter long is _______.
- correct answer. 0.67 m
One string on a toy guitar is 35.0 cm long. The string is plucked and the speed of waves
on the string is 420. m/s. What is the frequency of the third harmonic (n =3)? - correct
answer. 1800 Hz
A fife often has two openings in the pipe. A 25 cm pipe is played in air that has a speed
of sound of 400 m/s. What is the second harmonic's frequency? - correct answer.
1600 Hz
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