# Shared Flashcard Set

## Details

Edelman
chapter 3
50
Physics
05/28/2011

Term
 what is definition of parameters?
Definition
 describes the features of a sound wave
Term
 what is the source of a sound wave?
Definition
 ultrasound system and transducer
Term
 the tissue at which sound travels through is called what?
Definition
 medium
Term
 define period
Definition
 the time it takes a wave to vibrate a single cycle or the time from the start of one cycle to the start of the next cycle.
Term
 what are the units of period?
Definition
 seconds, ms (milliseconds), hours, days, ect.
Term
 can a sonographer change the period while using an ultrasound system with a particular transducer?
Definition
 no
Term
 define frequency
Definition
 the number of particular events that occurs in a specific duratiion of time. or simply put, the number of cycles that occur in one second.
Term
 what are the units of frequency?
Definition
 units per second. ex: 1 cycle/second = 1 hertz (Ht).
Term
 another way to say Hertz as pertained to frequency is what?
Definition
 per second
Term
 period is determined by the _______ only, not the medium.
Definition
 sound source
Term
 frequency of a sound wave is determined by the ___________only, not by the medium.
Definition
 sound source
Term
 can the sonographer change the frequency while using an ultrasound system and tranducer?
Definition
 no
Term
 sound waves less than 20Hz is called _____
Definition
 infrasonic
Term
 sound waves between 20Hz and 20,000 Hz frequencies is called _________
Definition
 audible sound
Term
 sound waves of 20,000 Hz (20kHz) or higher is called__________
Definition
 ultrasound
Term
 frequency is important to diagnostic sonography because it affects ____________
Definition
 penetration and image quality
Term
 period and frequency are __________ related to each other
Definition
 inversely
Term
 if frequency increases, period __________
Definition
 decreases
Term
 period X frequency = _________
Definition
 1
Term
 a wave with the lowest frequency has the ___________ period.
Definition
 longest
Term
 a wave with the shortest period has the ____________ frequency
Definition
 highest
Term
 what are the parameters of magnitude?
Definition
 amplitude, power, intensity
Term
 define amplitude
Definition
 the difference between the maximun average and the average value as well as the difference between the minimun value and the average value.
Term
 can a sonographer control the amplitude on an ultrasound system?
Definition
 yes
Term
 how is amplitude measured?
Definition
 fro the middle value (baseline) to the maximum value
Term
 how is peak-to-peak amplitude measured?
Definition
 the difference between maximum and minimum values. or twice the value of amplitude
Term
 define power
Definition
 rate of energy is transferred or rate at which work is performed
Term
 what are the units of power?
Definition
 watts
Term
 can a sonographer change the power of an ultrasound system.
Definition
 yes
Term
 define intensity
Definition
 the concentration of energy in a sound beam
Term
 what is the units for intensity?
Definition
 W/cm2 (watts per centimeters squared)
Term
 can a sonographer change the intensity of an ultrasound system?
Definition
 yes
Term
 intensity is proportional/nonproportional to the power?
Definition
 proportional
Term
 in a wave's power is doubled, what happens to the intesity?
Definition
 it doubles
Term
 in a wave's power is doubled, what happens to the intesity?
Definition
 it doubles
Term
 if wave's power is quartered, what happens to the intensity?
Definition
 it is quartered
Term
 intensity is proportional to the a wave's amplitude squared? true or false
Definition
 true
Term
 if a wave's amplitude is doubled, the intensity increases by how much?
Definition
 four times its origianl value
Term
 define wavelenght
Definition
 the distance or length of one complete cycle
Term
 wavelength is the only parameter that is determined by _________
Definition
 source and medium
Term
 the wavelength can/cannot be changed by the sonographer using an
Definition
 cannot
Term
 what two characteristics of a medium affect the speed of sound?
Definition
 stiffness and density
Term
 _________ describes tha ability of an object to resist compressions.
Definition
 stiffness
Term
 __________ describes the relative weight of a material.
Definition
 density
Term
 stiffness and speed are directly or inversly related to each other?
Definition
 directly
Term
 density and speed are directly or inversely related to each other?
Definition
 inversely related
Term
 material that are stiff but not dense will have a faster or slower speed?
Definition
 faster
Term
 materials that are not stiff and very dense will have a faster or slower speed?
Definition
 slower
Term
 when density increases, speed _________
Definition
 decreases
Term
 when stiffness increases, speed ________
Definition
 increases
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