# Shared Flashcard Set

## Details

Physics boards 1
test questions
79
Physics
04/22/2011

Term
 all numerical values should have corresponding____
Definition
 units
Term
 length is measured in?
Definition
 cm, feet, etc
Term
 area is measured in
Definition
 cm squared, feet squared, etc
Term
 volume is measured in
Definition
 cm^3, ft ^3, etc
Term
 T/F percent is not a unit
Definition
 True
Term
 increase by a factor of means
Definition
 to multiply by that number
Term
 decrease by a factor of means
Definition
 divide by that number
Term
 name the metric system and the corresponding powers
Definition
 The great(^9) majestic(^6) king(^3) henry(^2) died(^1) unexpectdely(^0) drinking(^-1) chocolate(^-2) malted(^-3) milk(^-6) not(^-9) pepsi()
Term
 micro is what power and what decimal notation? (ex 10^2, 100)
Definition
 micro is 10^-6, 0.000001
Term
 how many hertz is 3 MHz?
Definition
 3,000,000
Term
 how much bigger is a billion than a million?
Definition
 1,000 times
Term
 how many milliliters are contained in a jar filled with 5 liters of fluid??
Definition
 5,000
Term
 how many liters are in 80 ml of fluid?
Definition
 0.08
Term
 what is 10^-6 divided by 10^-3
Definition
 10^-3
Term
 what is 10^-6 sec/10^-3 sec?
Definition
 10 ^-3
Term
 acoustic propagation properties are...
Definition
 the effects of the medium upon the sound wave
Term
 biological effects are....
Definition
 the effects of the sound wave upon the biological tissues
Term
 compressions are in increase in______ or ___________.
Definition
 pressure, density
Term
 rarefactions are a decrease in _______or________
Definition
 pressure, density
Term
 T/F sound must travel through a medium and is amechanical, longitudinal wave that travels in a straight line.
Definition
 true
Term
 T/F: acoustic variables identify certain sound waves as sound waves
Definition
 true
Term
 what are the characteristics of an acoustic variable?
Definition
 pressure, density, distance, temperature
Term
 define pressure and give its units.
Definition
 pressure is the concentration of force within an area, force/area. units= pascals(Pa) NOT MMHG
Term
 what are the parameters that describe a sound wave?
Definition
 period, freq, amplitude, power, intensity, speed, wavelength
Term
 period: define, units, typical values, determine by, change by sonographer?
Definition
 =time recquired to complete a single cycle. units=time, typical values=0.1 to 0.5 micro sec, determined by sound source,  sonographer cannot change.
Term
 define frequency and units
Definition
 number of certain events that occur in a particular time duration. units= per second, hertz
Term
 frequency typical values, determined by, and can it be changed by the sonographer?
Definition
 typical values= 2MHz-10 MHz, determine by the sound source, cannot be changed by the sonographer.
Term
 A wave with the frequency exceeding 20,000 Hz (20KHz) is what type of sound
Definition
 ultrasound
Term
 audible sound is between what frequencies?
Definition
 20 Hz and 20,000Hz
Term
 sound with frequencies less than 20 Hz is?
Definition
 infrasound
Term
 how are frequency and period related?
Definition
 p= 1/f, so they are inveresly related.
Term
 define amplitude and its units
Definition
 the difference between the avg value and the max value  of an acoustic variable. units= acoutic variables (PDDT), decibels
Term
 amplitude;  is determined by, can it be changed by the sonographer?
Definition
 determined by the sound source, can be changed by the sonogrpaher
Term
 what is power and its units?
Definition
 the rate that work is preformed, or the rate of energy transfer. untis= watts
Term
 power is determined by the, can it be changed bythe sonographer?
Definition
 determined by the sound source, yes it can be changed by the sonographer
Term
 how are power and amplitude related?
Definition
 power is proportional to amplitude squared.
Term
 if the amplitude is doubled, what happens to the power?
Definition
Term
 define intensity and its unites
Definition
 it is the concentration of energy in a sound beam.  units= watts/cm^2
Term
 what is the intensity equation?
Definition
 I=power(watts)/area(cm^2)
Term
 what is intenisty determined by and can a sonographer change it?
Definition
 determined by the sound source, and yes a sonographer can change it.
Term
 typical value of intensity?
Definition
 0.001-100 watts/cm^2
Term
 T/F intensity decreases as sound propigates through the body
Definition
 T
Term
 what is the relationship of intensity and amplitude?
Definition
 intensity is related to amp^2
Term
 define waveleangth and its units
Definition
 it is the length or distance of a single cycle.  units=length
Term
 wavelength: determined by, can sonographer change it?
Definition
 determined by BOTH sound source and medium, cannot be changed by the sonographer
Term
 wavelength typical values
Definition
 0.1-0.8 mm (in soft tissue)
Term
 what is the equation for wavelength?
Definition
 wavelength= prop speed (c)/ frequency(MHz)
Term
 so soft tissue has a wavelength of 1.54mm with 1 MHz, what is the wavelegth of soft tissue with 2 MHz?
Definition
 0.77 mm
Term
 define prop speed
Definition
 rate at which sound travels through a medium. units= m/sec. determined by prop speed, and sonographer cannot change
Term
 what is the prop speed of soft tissue?
Definition
 1540m/s  1.54mm/microsec
Term
 how are speed and wavelength related?
Definition
 directly. fast speed/medium, long wavelength
Term
 what is the order of tissue propigation speeds (hint, a fat bloody....)
Definition
 a fat(1450) bloody waiter served(1540) bloody mashed bone(2000-4000). *m/s
Term
 how are stiffness and density related to speed?
Definition
 S&S- directy related S&D - inversly related
Term
 what are other names for density?
Definition
 compressability, elasticity
Term
 is bulk modulus the same as stiffness?
Definition
 yes
Term
 what is the equation for speed?
Definition
 speed= freq x wavelength
Term
 T/F you need to waves to create interferance?
Definition
 T
Term
 T/F: in diagnostic U/S imaging, short bursts, or pulses, of acoustic energy are used to create anatomic images
Definition
 T
Term
 define pulse
Definition
 a pulse is a collection of cycles that trave together. composed of on and off times.
Term
 what are the 5 parameters of pulsed U/S
Definition
 pulse duration, PRP, PRF, SPL, Duty factor
Term
 define pulse duration: units
Definition
 the time from start of a pulse to the end of that pulse, the actual time that the pulse is ON. units=time
Term
 pulse duration: determined by, change by sonographer, typical values
Definition
 determined by sound source, sonographer change. typical values=0.5-3microsec, a pulse is comprised of 2-4 cycles
Term
 pulsed duration equation:
Definition
 Pd= #cyces in pulse x period Pd= #cycles in pulse/freq
Term
 define PRP and units
Definition
 the time from the start of one pulse to the start of the next pulse. one on time and one off time.  units =time
Term
 PRP: determined by, can sonographer change, typical values
Definition
 determined by sound source, yes sonographer can change, typical values= 100microsec to 1msec
Term
 T/F: depth= PRP
Definition
 T
Term
 define PRF and its units
Definition
 PRF is the number of pulses that occur in one second. units= Hz, per second
Term
 PRF: determined by, can sonogrpaher change, typical values
Definition
 determined by sound source, yes sonographer can change, tpyical values=1,000-10,000Hz (1-10KHz)
Term
 how is PRP and PRF related?
Definition
 they are inversely related. increase PRP/depth and you decrease PRF
Term
 define Duty Factor and units
Definition
 the percetage/fraction of time that the system transmitts sound. UNITLESS (%)
Term
 DF: determine by, can sonographer change it, typical values
Definition
 determined by the sound source, yes the sonographer can change it, typical units=0.1 to 1 %
Term
 T/F: CW sound cannot be used to make anatomical images
Definition
 T
Term
 DF equation
Definition
 DF(%)=PD/PRP x100
Term
 Spatial Pulse length define and units
Definition
 the distance from the start to the end of one pulse.  units=length
Term
 SPL: determined by, can sonographer change, typical values:
Definition
 determined by BOTH source and medium. no sonographer cannot change. typical values=0.1-1mm
Term
 SPL helps to determine ___
Definition
 axial resolution
Term
 T/F SPL helps determine AR
Definition
 T
Term
 T/F shorter pulses help create higher quality images
Definition
 T
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