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sound waves are: - correct answer longitudinal and mechanical
The speed of US in soft tissue is closest to: - correct answer1,500 m/s
the frequency closest to the lower limit of ultrasound is: - correct answer15,000Hz
which is not an acoustic variable? - correct answer intensity
the effects of soft tissue on US are called: - correct answer acoustic propagation
properties
all the following are true EXCEPT - correct answer two waves with identical frequencies
must interfere constructively
put in decreasing order: deca, deci, micro, centi - correct answer deca, deci, centi, &
micro
______ is the time to complete one cycle. - correct answer period
which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
- correct answer 30 KHz
what is the frequency of a wave with 1 msec period? - correct answer1 kHz
______ is the distance covered by one cycle. - correct answer wavelength
which of the following is determined by the source and the medium? – correct answer
range resolution
propagation speed = ______ x wavelength - correct answer frequency
as a result of ______ the propagation speed increases. - correct answer decreasing
compressibility and decreasing density
put in decreasing order of propagation speed: gas, liquid, solid - correct answer solid,
liquid, gas
in the same medium, if the frequency of US is increased from 0.77MHz to 1.54 MHz,
what happens to the wavelength? - correct answer halved
,a sound wave's frequency is 10 MHz. the wave is traveling in soft tissue. what is its
wavelength? - correct answer0.15 mm
if the frequency of an US wave is doubled, what happens to the period? - correct
answerhalved
if the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the
propagation speed? - correct answerremains the same
the units of pulse repetition frequency are - correct answerper minute
the time from the beginning of a pulse until its end is _____? - correct answerpulse
duration
what happens to the speed of sound in a medium when the bulk modulus of the medium
increases? - correct answerfaster
______ resolution is determined by the spatial pulse length. - correct answerradial &
axial
if a wave's amplitude is doubled, what happens to the power? - correct
answerquadrupled
power of sound has units of - correct answerwatts
if the intensity of a sound beam remains unchanged while the beam area is reduced in
half, what has happened to the power? - correct answerhalved
which of these intensities is smallest? SATP, SPTP, SATA - correct answerSATA
the duty factor for continuous wave ultrasound is - correct answer1.0
what is the minimum value of the duty factor? - correct answer0.0%
what are the units of intensity? - correct answerwatts/cm squared
what happens to the speed of sound in a medium when the bulk modulus of the medium
decreases? - correct answerslower
the units of attenuation are _____; this is a ______ scale. - correct answer dB,
logarithmic
sound intensity is decreased by 75%. how many decibels of attenuation is this? - correct
answer6 dB
, the fundamental frequency of a transducer is 2.5 MHz. what is the second harmonic
frequency? - correct answer5 MHz
a pulse is emitted by a transducer and is traveling in soft tissue. the go-return time, or
time-of-flight, of a sound pulse is 130 microseconds. what is the reflector depth? -
correct answer10 cm
if a 5 MHz sound wave is traveling in the tissues listed below, which will have the
shortest wavelength? - correct answerair
if a 5 MHz sound wave is traveling in the tissues listed below, which will have the
longest wavelength? - correct answerbone
what is the approximate attenuation coefficient of 1 MHz US in soft tissue? - correct
answer0.5 dB/cm
the rayl is the unit of: - correct answerimpedance
impedance is the ______ of ______ and ______. - correct answerproduct, propagation
speed, density
what are attenuation's three components? - correct answerscattering, reflection,
absorption
for soft tissue, the approximate attenuation coefficient in dB/cm is equal to one-half
_____ in ______. - correct answerfrequency, MHz
as the impedances of two media become vastly different, the - correct answerreflection
increases
the angle between an US pulse and the boundary between two media is 90 degrees.
what is this called? - correct answerorthogonal incidence
the angle between an US pulse and the boundary between two media is 56 degrees.
this is called: - correct answeroblique incidence
refraction only occurs if there are: - correct answeroblique incidence and different
propagation speeds
with normal incidence, what factors affect refraction of US? - correct answernone of the
above
T/F: with right angle incidence, reflections are always generated at a boundary if the
propagation speeds of the media are different. - correct answerfalse