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54 Cards in this Set
- Front
- Back
Repetitious waves are a _______ transfer of energy.
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cyclical
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The major classification of waves are _____ and _____.
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electromagnetic and mechanical
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An electromagnetic wave does not need a _____ to propagate.
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medium
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A _____ wave needs a medium to propagate.
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mechanical
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There can be no _____ waves is a vacuum.
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mechanical
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A vacuum is an absence of a _____.
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medium
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There is no sound in a ______, since there is no medium.
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vacuum
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Two classifications of mechanical waves are _____ and _____.
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transverse and longitudinal
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In a _____ wave, particle motion is perpendicular or "transverse" to the wave direction.
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transverse
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In a _____ wave, the particle motion is back and forth "longitudinally" or in the same direction as the wave propagation.
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longitudinal
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Sound is a _____, mechanical wave.
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longitudinal
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A longitudinal wave has areas or _____ and compression.
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rarefaction
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An area of _____ is where the particles are farther apart than the normal state.
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rarefaction
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An area of _____ is where the particles are closer together than the normal state.
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compression
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Not all waves need a medium to propagate; _____ electromagnetic waves can operate in a vacuum.
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electromagnetic
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_____ is a way of specifying how fast a wave is cyclically varying.
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frequency
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The unit of frequency is _____ which is an abbreviation for cycles per second.
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Hertz
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Frequency has units which are the inverse of _____, or one divided by seconds, also called Hz.
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time
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The number of times a longitudinal wave reaches maximum compression and rarefaction per time is called the _____.
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frequency
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The reciprocal of frequency is the _____.
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period
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The period has units of _____.
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time
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The reciprocal of the _____ is frequency. Frequency has units of Hertz.
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period
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The _____ is the time between cycles of peak compression in a longitudinal wave such as sound.
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period
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The _____ between cycles of peak compression is the same as the time between cycles of peak rarefaction.
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time
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The ____ is the time between cycles of peak rarefaction.
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period
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Frequency and period are _____.
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reciprocals
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Hertz and _____ or seconds are inversely related.
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time
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Since frequency and period are inversely related, if the frequency increase the period _____.
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decreases
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A shorter period means higher _____.
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frequency
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A lower _____ means a longer period.
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frequency
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The ______ is the physical measure of distance between wave peaks or similarly wave minima.
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wavelength
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Wavelength is a measure of _____ and therefore in the metric system has units of meters.
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distance
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The period is a measure of ____ between peaks whereas the wavelength is a measure of distance between peaks.
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time
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Frequency and _____ are related through the wave propagation velocity.
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wavelength
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The propagation of _____ has units of meters/second.
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velocity
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The ______ is a measure of how fast a wave will travel.
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propagation velocity
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The propagation of velocity (c) equals the frequency (f) times the _____.
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wavelength
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For a given propagation velocity, if the frequency increases, the _____ must decrease.
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wavelength
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For a given propagation velocity, if the frequency decreases, the wavelength must _____.
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increase
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Frequency and wavelength have a _______ relationship.
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inverse
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If the propagation velocity changes, and the frequency is not changed, the ______ must change.
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wavelength
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The ______ of a signal is a measure of how big or loud it is.
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amplitude
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The ______ is determined as the maximum variation from the mean.
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amplitude
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mean
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(maximum+minimum)/2
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If the _____ of an ultrasound echo increases, the B-mode image will get brighter.
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amplitude
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Possible units of amplitude are:
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Pascals, degrees Celsius, meters, kg/m
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A wave which has a physical interaction with the medium is called a _______ wave.
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mechanical
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A change within the medium caused by a wave is called a ______.
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variable
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List the 4 acoustic variables:
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pressure, distance, temperature, density
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Units of pressure are:
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Pascals, Atmospheres, mmHG, kg/m2, lbs/in2
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Units of distance are:
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meters, feet, miles, yards, etc
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Units of temperature are:
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degrees Celsius, degrees Fahrenheit, degrees Kelvin
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Units of density are:
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mass/volume, such as kg/m3 or lbs/ft3
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Changes in the acoustic variables are the result of the ____ interaction of the acoustic wave and the medium.
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mechanical
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