Chapter 2 - 14.3 questions Flashcards
What is the wavelength of 5 MHZ ultrasound in soft tissue ?
0.3 mm
What is the wavelength of 10 MHz in bone ?
0.4 mm
Given a wavelength of 1 mm and a frequency of 2MHz, what is the propagation velocity ? Do you think this medium is stiffer than soft tissue , blood bone ?
2000 m/sec
Stiffness is ____________ related to compressibility , _______ related to elasticity _______- related to inelasticity
inversely related
inversely related
directly related
If the transmit voltage is increased from 2 - 4 volts , the frequency will ______-
not change
Frequency of ultrasound, infrasound, audible, and diagnostic ultrasound
infrasound 0-20 Hz
audible 20-20 kHz
ultrasound >20 kHz
diagnostic ultrasound 2 MHz - 10 MHz
What happens to the intensity if the amplitude is increased by a factor of 3.
intensity increase by a factor of 9
What happens to the intensity if the power is increased by a factor of 3 ?
intensity increases by a factor of 3
What happens to the intensity if the area is increase by a factor of 2 ?
intensity decrease by a factor of 2
If we keep the area fixed, and if the intensity increases by a factor of 4, what change has occurred to the amplitude?
Amplitude has increase by a factor of 2
The frequency is determined strictly by the wave __________
source
The period of a wave is det. strictly by the wave __________
source
The propagation velocity is det. strictly by the properties of the _________.
medium
The 2 two properties of the medium which determine the propagation velocity are _____________ (related to density) and _____ (related to compressibility and stiffness)
inertia
elasticity
The propagation velocity ___________ with increased density (assume no change in stiffness)
decreases
As the density decreases, the propagation velocity ________ (assume no change in stiffness)
increases
A stiff material is not very elastic , so stiffness and elasticity are ________ related.
inversely
A material which is inelastic is a stiff material and therefore has a high __________ velocity.
propagation
Inelasticity and incompressibility are related to ___________
stiffness
Elasticity and ________ are inversely related to stiffness
compressibility
A gas is generally more compressible than a __________ which is generally more compressible than a solid.
a liquid
____________ is sound below human hearing
infrasound
___________ is sound above human hearing.
Ultrasound
___________ ultrasound is approximately from 2MHz to 10 MHz.
Diagnostic
All sound waves are _______ mechanical waves.
longitudinal
Infrasound is below ________.
20 Hz
Ultrasound is any sound above _________.
20kHz
_____________ is the rate at which energy is transferred
power
___________ is proportional to the (amplitude)^2
Power
If the amplitude is doubled, the power is _______-
quadrupled
If the amplitude is decreased by a factor of 2, the power is decreased by a factor of ________-
four
Power is a measured in units of __________
watts
The _________ is defined as the concentration of energy
intensity
The fundamental units for __________ is power per area
intensity
If power is given in Watts and the area is given in ________ the intensity has units of watts/cm^2
cm^2
If the area is increased by a factor of 2 and the power is unchanged , the intensity is decreased by a factor of ________
two
If the power increases by a factor of 2 and the area is unchanged, the intensity ___________ by a factor of________.
increases
2
If the amplitude doubles, the power ______ . If the area is not changed , the intensity is also ________-
quadruples
quadruples
Intensity is proportional to the ____________ which is proportional to the ___________ squared
power
amplitude
The intensity is inversely proportional to the _________.
area
