chapter 2 Flashcards
Electromagnetic waves
a) do not transfer energy
b) cannot propagate through a medium
c) include sound waves
d. none of the above
D
Mechanical waves must have a _____________ to propagate.
medium
Sound is an ___________ wave.
mechanical
All wave transport _______________.
energy
A mechanical wave implies an interaction between the wave and the ___________.
medium
If a wave needs a medium to propagate it is an ______________ wave
mechanical
If a wave does not need a medium to propagate it is an ___________ wave.
electromagnetic
Which is the following is not an example of an electromagnetic wave ? (more than one can apply)
a. x-rays
b. light
c. sounds
d. heat
e. television signals
c
All waves are an _________________ transfer most often through cyclical variations.
a. particle
b. energy
c. voltage
d. temperature
b
The naming of waves as mechanical is due to the physical interaction between the wave and the medium. The interaction produces 4 specific possible changes called ______________ variables
1)
2)
3)
4)
acoustic
pressure
density
temperature
distance
All of the following are acceptable units of pressure except :
a. Pascal
b. lb/in^2
c. kg/m^2
d. lb/ft
e. atm
f. mmHg
d
Density is defined as
a. mass/volume : kg/m^3
b. mass/volume : kg/m^2
c. volume/mass : m^3/kg
d. mass x volume : m^3kg
a
Sound is a ___________ , ____________ wave.
a. longitudinal, electromagnetic
b. longitudinal, mechanical
c. transverse, electromagnetic
d. transverse, mechanical
b
For a longitudinal wave, the energy is transported by a series of _______ and _________ of the medium particles.
compressions and rarefactions
Repetitious wave are a ________ transfer of ______________.
cyclical
energy
Cyclical means
a. periodic or repetitive
b. in a circle
c. linear
a.
The major classifications of waves are ________ and _________.
electromagnetic
mechanical
Examples of electromagnetic waves are
a. TV, microwave and sound
b. music, ultrasound and ocean waves
c. x-rays , light and microwaves
c
A _________ wave needs a medium to propagate.
mechanical
A vacuum is the absence of a _________
medium
Two classifications of mechanical waves are _______ and ___________
transverse
longitudinal
In a __________ wave, particle motion is perpendicular or transverse to the wave direction
transverse
In a ____________ wave, the particle motion is back and forth in the same direction as the wave propagation.
longitudinal
Sounds is a ____________, mechanical wave.
longitudinal
A longitudinal wave has areas of ___________ and compression
rarefaction
An area of _____________ is where the particles are father apart than the normal state
rarefaction
___________ is a way of specifying how fast a wave is cyclically varying.
frequency
The unit of frequency is ___________ , which is an abbreviation for cycle per __________.
hertz, second
Frequency has units which are the inverse of _______, or one divided by ____________, also called Hz.
time, second
The number of times a longitudinal wave reaches maximum compression and rarefaction per time is called the __________.
frequency
The reciprocal of frequency is the __________.
period
The period has units of ______
time
The __________ is the time between cycles of peak compression in a longitudinal wave, such as sound.
period
Frequency and period are ___________.
reciprocals
Hertz and __________ (or seconds) are inversely related.
time
A shorter period means a higher _________.
frequency
The _________ is the physical measure of distance between wave peaks (maximum) or similar wave.
wavelength
Wavelength is a measure of _________ and therefore in the metric system has units of __________.
distance, meters
Frequency and ___________ are related through the wave propagation velocity.
wavelength
The propagation _____________ has units of meters/sec
velocity
The ______ ___________ is a measure of how fast a wave will travel.
propagation velocity
The propagation velocity equals the frequency times the ________-
wavelength
Frequency and wavelength have an _____________relationship
inverse
If the propagation velocity changes and the frequency is not changed the ________ must change.
wavelength
The _______ of a signal is a measure of how big or loud it is.
amplitude
The _________ = maximum+ minimum /2
amplitude
The difference between the maximum and the mean is the as the difference between the mean and the ____________
minimum
If the _________ of an ultrasound echo increases, the B-mode image will get brighter.
amplitude
If the _________ of a Doppler echo __________-, the Doppler audio will get louder.
amplitude,
increases
Amplitude is used to measure any wave variable. For sound waves, the units of amplitude will be any measure of the 4 __________ variables.
acoustic
For electrical waves, __________ is used to measure any wave parameters of electric variables such as voltage.
amplitude
Some possible units of _________ are Pascals, degrees celcius , meters, kg/m^3
amplitude
A change within the ___________ caused by a wave is called a variable.
medium
For an acoustic wave, the changes caused to the medium are called _________ variables.
acoustic
Units of _____________ are : Pascals , Atm, mmHg, kg/m^2, lbs/in^2
pressure
Units of _________ are : meters, feet, miles, yards , etc.
distance
Units of ______ are masse/volume such as kg/m^3 and lbs/ft^3
density
Changes in acoustic variables are the results of the mechanical interaction of the acoustic wave and the ________
medium
What is the frequency in Hertz, of something that occurs 60 times in 1 minute
1 hz
What is the frequency in hertz, of something that occurs 60 times in 0.1 sec ?
600 hz
What is the frequency in Hertz of something that occurs 60 times in 1 hour ?
1/60 hz
What determines the frequency of operation for ultrasound ?
a. medium
b. pulser
c. patient
d. wavelength
b
How much will the frequency change if the propagation velocity changes by the factor of 2 ?
Frequency will not change.
Frequency is det. by the source and not the medium
If the frequency is 1 MHz, what is the period?
1 micro sec
If the period is 0.5 microsec , what is the frequency ?
2 MHZ
Which 2 of the following give the same information ?
a. frequency = 10 kHZ
b. frequency = 3kHZ
c. period = 0.1 msec
d. period = 10 ksec
a+ c
What determines the period for ultrasound ?
a. medium
b. pulser
c. patient
d. wavelength
b.
How much will the period change if the propagation velocity changes by a factor of 2?
The period will not change
If ultrasound travels 662 meters through air in 2 seconds, what is the propagation velocity of sound in air in m/sec?
331 m/s
How far can a car travel in 2 hours driving at 60 mph?
120 miles
How far can an ultrasound beam travel in soft tissue in 1 second ?
1540 m
How long would it take a car travelling 30 mph to travel 45 miles ?
1.5 hour
How long would it take ultrasound in soft tissue to travel to a target 1cm deep and back to the transducer ?
13 micro second
The speed of sound
a. changes with frequency
b. change with period
c. depends on inertia and elasticity of medium
c
The wavelength has units of
a. time
b. events/time
c. distance/time
d. distance
d
If the propagation velocity is unchanged but the frequency changes , the wavelength
a. will change
b. will remain constant
c. cant be determined
a
If the frequency is unchanged but the propagation velocity changes, the wavelength
a. changes
b. remain constant
c. cant be determined
a
