EDELMAN: COMPREHENSIVE EXAM
QUESTIONS AND ANSWERS 100% CORRECT!
,sound waves are? - ANSWER longitudinal, mechanical
the speed of US in soft tissue is closest to: - ANSWER 1,500 m/s (1,540 m/s)
the frequency closest to the lower limit of US is: - ANSWER 15,000 Hz
which is not an acoustic variable? - ANSWER intensity
the effects of soft tissue on US are called: - ANSWER acoustic propagation properties
all of the following are true except: - ANSWER two waves with identical frequencies
must interfere constructively
put in decreasing order: - ANSWER deca, deci, centi, micro
______________ is the time to complete one cycle - ANSWER period
which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
- ANSWER 30 KHz
what is the frequency of a wave with 1msec period? - ANSWER 1 kHz
_____________ is the distance covered by one cycle - ANSWER wavelength
Which of the following is determined by the source and the medium? - ANSWER range
resolution
propagation speed = ________ x wavelength - ANSWER frequency
as a result of ____________ the propagation speed increases - ANSWER decreasing
compressibility and decreasing density
put in decreasing order of propagation speed - ANSWER solid, liquid, gas
if the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the
wavelength? - ANSWER halved
, a sound wave's frequency is 10MHz. the wave is traveling in soft tissue. what is its
wavelength? - ANSWER 0.15 mm
if a wave's amplitude is doubled, what happens to the power? - ANSWER quadrupled
if the level of an acoustic variable ranges from 55 to 105, what is the amplitude? -
ANSWER 25
power of sound has units of? - ANSWER watts
if the intensity of a sound beam remains unchanged while the beam area is reduced in
half, what has happened to the power? - ANSWER halved
which of these intensities is smallest? - ANSWER SATA
the duty factor for continuous wave ultrasound is? - ANSWER 1
what is the minimum value of the duty factor? - ANSWER 0.0%
what are the units of intensity? - ANSWER watts/cm2
what happens to the speed of sound in a medium when the bulk modulus of the medium
decreases? - ANSWER slower
the units of attenuation are _________; this is a ____________ scale. - ANSWER dB,
logarithmic
sound intensity is decreased by 75%. how many decibels of attenuation is this? -
ANSWER 6 dB
the fundamental frequency of a transducer is 2.5 MHz. what is the second harmonic
frequency? - ANSWER 5 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? -
ANSWER 10cm
if a 5MHz sound wave is traveling in the tissues listed below, which will have the longest
wavelength? - ANSWER bone
QUESTIONS AND ANSWERS 100% CORRECT!
,sound waves are? - ANSWER longitudinal, mechanical
the speed of US in soft tissue is closest to: - ANSWER 1,500 m/s (1,540 m/s)
the frequency closest to the lower limit of US is: - ANSWER 15,000 Hz
which is not an acoustic variable? - ANSWER intensity
the effects of soft tissue on US are called: - ANSWER acoustic propagation properties
all of the following are true except: - ANSWER two waves with identical frequencies
must interfere constructively
put in decreasing order: - ANSWER deca, deci, centi, micro
______________ is the time to complete one cycle - ANSWER period
which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
- ANSWER 30 KHz
what is the frequency of a wave with 1msec period? - ANSWER 1 kHz
_____________ is the distance covered by one cycle - ANSWER wavelength
Which of the following is determined by the source and the medium? - ANSWER range
resolution
propagation speed = ________ x wavelength - ANSWER frequency
as a result of ____________ the propagation speed increases - ANSWER decreasing
compressibility and decreasing density
put in decreasing order of propagation speed - ANSWER solid, liquid, gas
if the frequency of US is increased from 0.77 MHz to 1.54 MHz, what happens to the
wavelength? - ANSWER halved
, a sound wave's frequency is 10MHz. the wave is traveling in soft tissue. what is its
wavelength? - ANSWER 0.15 mm
if a wave's amplitude is doubled, what happens to the power? - ANSWER quadrupled
if the level of an acoustic variable ranges from 55 to 105, what is the amplitude? -
ANSWER 25
power of sound has units of? - ANSWER watts
if the intensity of a sound beam remains unchanged while the beam area is reduced in
half, what has happened to the power? - ANSWER halved
which of these intensities is smallest? - ANSWER SATA
the duty factor for continuous wave ultrasound is? - ANSWER 1
what is the minimum value of the duty factor? - ANSWER 0.0%
what are the units of intensity? - ANSWER watts/cm2
what happens to the speed of sound in a medium when the bulk modulus of the medium
decreases? - ANSWER slower
the units of attenuation are _________; this is a ____________ scale. - ANSWER dB,
logarithmic
sound intensity is decreased by 75%. how many decibels of attenuation is this? -
ANSWER 6 dB
the fundamental frequency of a transducer is 2.5 MHz. what is the second harmonic
frequency? - ANSWER 5 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? -
ANSWER 10cm
if a 5MHz sound wave is traveling in the tissues listed below, which will have the longest
wavelength? - ANSWER bone
