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46 Cards in this Set

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Definition of Sound
mechanical, longitudinal wave that travels in a straight line
A sound wave is made up of what two things?
compression and rarefaction
Define Period and state unit
length of time it takes to complete a single cycle
seconds
What parameters can be changed by the sonographer?
Amplitude, power and intensity
What parameters are determined by the sound source only?
Period, Frequency, amplitude, power, and intensity.
What parameter are determined by both sound source and medium?
wavelength
What parameter is determined by the medium only?
propagation speed
Define propagation speed and state unit
speed at which sound moves through a medium
m/second
State the relationship between speed and density, and speed and stiffness.
if density increases, speed decreases
if stiffness increases, speed increases
Put the following things in order of speed from slowest to fastest...
liquid, solid, gas
gas, liquid, solid
Put in order the following things in order of slowest to fastest..brain, kidney, liver, air, soft tissue, and muscle.
air, brain, soft tissue, liver, kidney, muscle
What is the speed of sound through soft tissue?
1540m/s or
1.54 km/s or
1.54 mm/us
define mathematically propagation speed.
propagation speed= frequency (Hz)* wavelength (m)
Define Frequency and state unit
the # of certain events that occur in a specific duration of time
1/sec or Hertz
Define the ranges for infrasound, audible sound and ultrasound.
Infrasound= <20 Hz
audible sound=20Hz-20kHz
ultrasound= >20kHz
what is the clinical imaging range for period?
.1 to .5us
What is the clinical imaging range for frequency?
2MHz to 10MHz
What is the clinical imaging range for amplitude?
1MPa to 3MPa
What is the clinical imaging range for Power?
4-90mW
What is the clinical imaging range for intensity?
.01-300 W/cm^2
What is the clinical imaging range for Wavelength?
.1-.8mm
What is the clinical imaging range for propagation speed?
500 m/s to 4000 m/s
State the relationship between period and frequency, and wavelength and frequency?
They are inverse of each other
Can you change frequency without changing period?
no, frequency is determined by period.
Define amplitude and state its unit of measure
the strength of a wave-the magnitude of the wave
any units of acoustic variable, degrees, cm, grams/cubic cm, Pascals, decibels
Define power and state the unit of measure
relates to strength,
it is the rate in which work
is performed or energy is transferred from the entire sound beam
units: watts
state the relationship between power and amplitude
directly related, power=amplitude squared
state the relationship between intensity and amplitude
directly related, intensity=amplitude squared
Define intensity and state the unit of measure
relates to the strength of a sound beam, it is the concentration of energy in a sound beam
watts/cm ^2
Define intensity mathematically
intensity= power of a beam/ its cross sectional area
Define wavelength and state unit of measure
distance of length that one cycle occupies
mm, cm, or meter
define wavelength mathematically
wavelength= propagation speed(mm/us) / frequency (MHz)
which image would have better quality and longitudinal resolution?
A-high frequency, short wavelength
B-Low frequency, long wavelength
image A
If frequency increases what does period do?
decrease
What does amplitude, power and intensity do as sound propagates through the body?
they decrease
If amplitude is increased 3x than what does power do?
it is increased 9x
if amplitude is increased 3x than what does intensity do?
it is increased 9x
if power is doubled than what does intensity do?
it is doubled
If wavelength increases what does frequency do?
it decreases
What is density?
concentration of mass per unit of volume
What is stiffness?
materials ability to maintain it's shape
If density increases what does speed do?
it decreases
If stiffness increases what does speed do?
it increases
convert 3 seconds to million seconds and then to micro seconds
3 seconds= .000003 Ms or
3*10^6 seconds
3 secs= 3000000 us or
3*10^-6 seconds
name two complimentary unit relations
giga and nano (billion & billionths, 10^9 & 10-9)
mega and micro (million & millionths, 10^6 & 10^-6)
State the following units power of 10
giga, mega, kilo, hecto, deca, deci, centi, milli, ,micro, nano
10^9 giga
10^6 mega
10^3 kilo
10^2 hecto
10^1 deca
10^-1 deci
10^-2 centi
10^-3 milli
10^-6 micro
10^-9 nano