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53 Cards in this Set
- Front
- Back
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Q: What is the source of all sounds?
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A: vibrating objects
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Q: How does pitch relate to frequency?
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A: Pitch is subjective, but it increases as frequency increases
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Q: What is the average frequency range of a young person’s hearing?
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A: 20 Hz – 20,000 Hz
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Q: Distinguish between infrasonic and ultrasonic sound.
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A: Infrasonic – below 20 Hz and ultrasonic – above 20,000 Hz
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Q: Distinguish between compressions and rarefactions of a sound wave
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A: Compressions are regions of high pressure & rarefactions are regions of low pressure
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Q: How are compressions and rarefactions produced?
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A: Compressions & rarefactions are produced by a vibrating source.
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Q: What evidence can you cite to support the statement: Light can travel in a vacuum.
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A: you can see the sun or the moon
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Q: Can sound travel through a vacuum?
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A: No, sound needs a medium to travel
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Q: How does air temperature affect the speed of sound?
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A: Sound travels faster at higher temperatures.
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Q: How does the speed of sound in air compare with its speed in water & in steel?
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A: Sound travels faster in water & faster again in steel
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Q: Why does sound travel faster in solids an dliquids than in gases?
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A: The atoms are closer together, & solids and liquids are more elastic mediums
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Q: Why is sound louder when a vibrating source is held to a sounding board?
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A: More surface is forced to vibrate and push more air.
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Q: Why do different objects make different sounds when dropped on a floor?
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A: They have different natural frequencies.
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Q: What does it mean to say that everything has a natural frequency of vibration?
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A: The natural frequency is characteristic of the object’s shape, size, & composition.
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Q: What is the relationship between forced vibration and resonance?
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A: Resonance is forced vibration at the natural frequency.
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Q: Why can a tuning fork or bell be set into resonance, while tissue paper cannot?
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A: Tissue paper has no natural frequency.
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Q: How is resonance produced in a vibrating object?
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A: By input of vibrations at a frequency that matches the natural frequency of the object
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Q: What does tuning in a radio station have to do with resonance?
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A: By input of vibrations at a frequency that matches the natural frequency of the objects
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Q: Is it possible for one sound wave to cancel another? Explain
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A: Yes, it is destructive interference
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Q: Why does destructive interference occur when the path lengths from two identical
sources differ by half a wavelength? |
A: The crests of one coincide with the troughs of the other; canceling each other out.
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Q: How does interfernce of sound relate to beats?
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A: Beats are a result of periodic interference.
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Q: What is the beat frequency when a 494 Hz tuning fork & a 496 Hz tuning fork are
sounded together? And what is the frequency of the tone heard? |
A: beat frequency (496 – 494) Hz = 2 Hz tone heard is half way between 495Hz
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Q: When watching a baseball game, we often hear the bat hitting the ball after we
actually see the hit. Why? |
A: Light travels faster than sound
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Q: What 2 physics mistakes occurin a movie when you see & hear at the same time
a distant explosion in outer space? |
A: Distant sound should get to you after you see the light. Also, sound cannot travel in a
vacuum, so there would be not sounds transmitted in out space. |
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Q: Why will marchers at the end of a long parade following a band be out of step with
marchers nearer the band? |
A: There is a time delay for sound from a marching band near the front of a long parade
to reach the marchers at the end. |
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Q: When a sound wave propagates past a point in the air, what are the changes that occur in the pressure of air a this point?
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A: Air pressure increases and decreases at a rate equal to the frequency of the sound
wave |
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Q: If the handle of a tuning fork is held solidly against a table, the sound becomes louder.
Why? |
A: More surface vibrates and more air is pushed
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Q: If the handle of a tuning fork is held solidly against a table, the sound becomes louder.
How will this affect the length of the time the fork keeps vibrating? |
A: The time decreases because more sound energy is sent out so the tuning fork loses
energy more rapidly. |
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Q: What beat frequency would occur if two tuning forks ( 260 Hz & 266 Hz) are
sounded together? |
A: 263 Hz
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Q: Two notes are sounding, one of which is 440 Hz. If a beat frequency of 5Hz is heard,
what is the other notes’s frequency? |
A: Either 445 Hz or 435 Hz
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Q: Two sounds, one at 240 Hz and the other at 243 Hz., occur at the same time. What
beat frequency do you hear? |
A: (243 Hz- 240 Hz) = 3Hz
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Q: A longitudinal wave can also be called a ___ wave.
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A: a compression wave
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Q: A wave that resembles a transverse wave but occurs in mediums that are
fixed at both ends is call a ___ wave. |
A: a standing wave
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Q: When a wave is incident on a medium boundary and changes its direction due
to a change in the wave’s velocity, this wave behavior is called ___. |
A: refraction
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Q: When a wave encounters an obstacle in its path and spreads out (bends) around the
obstacle, this wave behavior is called ___. |
A: diffraction
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Q: The ___ of a sound wave depends on how much the matter carrying the wave is
compressed by each vibration. |
A: amplitude
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Q: true or false The frequency of a sound wave is the same as the frequency of the
vibration that produces the sound. |
A: True
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Q: Ultrasounds are sounds found above the ___Hz mark
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A: Ultrasounds are above 20,000 Hz.
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Q: The pitch of a train whistle appears to ___ as it approaches & ___ as it travels
away from an observer. |
A: pitch appears to increase as it approaches and decrease as it moves away
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Q: The field of study that analyzes the behavior of waves is called ___.
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A: acoustics
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Q: The multiple reflections of a sound wave is called ___.
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A: reverberation
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Q: true or false The greater the amount of energy created by a wave, the larger its
amplitude |
A: true
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Q: The intensity of sound is measured in ___.
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A: decibels
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Q: What 3 things can you do to a guitar string to decrease its frequency & pitch?
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A: Make the string 1. longer 2. thicker 3. decrease tension of string (loosen string)
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Q: When a wave changes from a straight wavefront to a curved front, this is called __.
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A: diffraction
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Q: This term refers to waves of the same frequency that are either in phase or out of
phase of each other. |
A: interference
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A common example of a transverse wave
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light.
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Bow waves are produced when waves of water
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move slower than the source producing them.
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When we consider the time it takes for a pendulum to swing to and fro, we're talking about its
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period.
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Standing waves are produced by
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interference.
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The Doppler effect is defined as an apparent change in wave
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frequency.
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A repeating, back-and-forth motion about an equilibrium position is
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a vibration.
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The vibrations along a longitudinal wave move in a direction
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along and parallel to the wave.
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