Chapter 3 Terms/Relationships
You need to know if
parameters are determined by the___ or the____.
sound source; medium
The ____ of a sound wave
is the ultrasound machine and/or the transducer.
source
The ____ is the tissue that
the sound is traveling through.
medium
What is the time it takes for a wave to complete/vibrate a single cycle?
Period
What is the start of one cycle to the start of the next cycle?
Period
What are the units of period?
Time
In ultrasound period is typically____.
0.06 to 0.5 microseconds
Can you change period?
No
What is the number of certain events that occur in a specific duration of time?
Frequency
The number if cycles that occurs in one second is _____.
frequency
What are the units for frequency?
per second, 1/second, hertz, or Hz
(2 million to 15 million cycles per second)
Frequency is determined by____.
sound source
1,000 Hz= 1_____
kHz
1,000,000 Hz= 1____
MHz
There is 8 cycles that occur in 4 seconds. The frequency is 8/4, or ____.
2 Hz
The wave's frequency is 4 per second, or ____.
4 Hz
If the frequency of a sound is less than___, it is too low for humans to hear.
20 Hz
Inaudible=____ or ____
infrasonic; infrasound
If we can hear the sound, the frequency must be between___ and____.
20 Hz; 20,000 Hz
A frequency between 20Hz and 20,000 Hz is _____.
audible
It sound has a frequency over ____, it is too high for humans to hear.
20,000 Hz (20 kHz)
If sound has a frequency that is too high for humans to hear it is____ or_____.
ultrasonic; ultrasound
What affects the ability of a sound wave to penetrate tissue and affects image quality?
Frequency
The affecting of the ability of a sound wave penetrating tissue and affecting image quality is called _____.
axial resolution
Period and frequency are _______.
inversely related
With period and frequency, frequency goes ____, period goes _____.
up; down
If frequency stays the same, the other_____.
stays the same
Period and frequency are _____.
Reciprocals
Period x Frequency=
1
What is one equation for period and frequency?
period (sec)= 1/frequency (Hz)
What is one equation for period and frequency?
Frequency (Hz) = 1/period (sec)
What is an example of a complimentary unit?
period 1x10 to the -6th is = frequency 1x10 to the 6th
Events per second is known as ____.
Hertz
When period is 1/8 second, frequency is ____ waves per second.
8
When the frequency is 8 waves per second, the period is _____ second.
1/8
What is amplitude?
The "bigness" of a wave
Amplitude is the difference between the ___ value and the ____ or ____ value of an acoustic variable.
maximum; avergage; undisturbed
What is the units of density?
g/cm cubed
Amplitude is determined by the ____.
sound source
____ is the rate of energy transfer or the rate at which work is performed.
Power
Units of power is ______.
Watts
Powers range from _____watts.
0.004 to 0.090
Power is determined by the ______.
sound source
Is power adjustable?
Yes
Both amplitude and power are parameters that describe the _____ or ______ or a wave.
size; magnitude
When power____, amplitude_____.
decreases; decreases
_____ is the concentration of energy in a sound beam.
Intensity
To calculate _____, divide the beam's power by the beam's cross-sectional area.
intensity
Intensity is determined by______ only.
sound source
Is intensity adjustable?
Yes
The 3 bigness parameters are ____; _____; and _____.
amplitude; power; intensity
_____ is the distance or length of one complete cycle.
Wavelength
Wavength is measured in units of_____.
mm, meters, or any other unti if length
Wavelength in soft tissure ranges from _____ to _____.
0.1; 0.8 mm
Wavelength is determined by_____.
Both
Can wavelength be adjusted?
No
Amplitude is always _____.
squared
_____ is the rate at which a sound wave travels through a medium.
Propogation speed
Propogation speed is measured in units of ______.
meters per second, mm/microsecond, or any distance divided by time
In the body, the speed if sound ranges frim ____ m/s to _____ m/s.
500; 4,000
Speed is determined by _____ only.
medium
Is speed adjustable?
No
The speed of sound in soft tissue is ______.
1,540 m/s (1.54 mm/microseconds or 1.54 km/s)
Sound travels ____ in solids, ____ in liquids, and ____ in gases.
fastest; slower; slowest
The 2 characteristics of a medium that affect the speed of sound are ___ and ____.
stiffness; density
____ describes the ability of an object to resist compression.
Stiffness
Stiffness and speed are _____.
directly related
_____ describes the relative weight of a material.
Density
Density and speed are _______.
inversely related
Power/Area= 1/2= 0.5. If the area is doubled 1/4= .25, 0.5 _______.
decreased by half
When stiffness _____, speed____.
increases; increases
When density _____, speed_____.
increases; decreases
Speed is determined by the ____ and _____ of the medium.
density; stiffness
Amplitude is measured from the baseline to _____, or from the baseline to ____.
maximum; minimum
Peak-to-peak amplitude is ____ that of amplitude.
twice