SPI PRACTICE QUESTIONS WITH COMPLETE SOLUTIONS.
Sound waves are: - correct answer. longitudinal, mechanical
The speed of sound in soft tissue is closest to: - correct answer. 1,500 m/s
The frequency closest to the lower limit of ultrasound is: - correct answer. 15,000 Hz
...
The speed of sound in soft tissue is closest to: - correct answer. 1,500 m/s
The frequency closest to the lower limit of ultrasound is: - correct answer. 15,000 Hz
Which is not an acoustic variable? - correct answer. intensity
The effects of soft tissue on ultrasound are called: - correct answer. acoustic
propagation properties
All of the following are true EXCEPT: - correct answer. two waves with identical
frequencies must interfere constructively
Put in decreasing order: deci, deca, 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? - correct answer.
30 KHz
What is the frequency of a wave with a 1 msec period? - correct answer. 1 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 density
,Put in decreasing order of propagation speed: gas, liquid, solid - correct answer. solid,
liquid, gas
If the frequency of US is increased from 0.77 MHz 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 answer. .15 mm
If the frequency of an US wave is doubled, what happens to the period? - correct
answer. halved
If the frequency of US is increased from 0.77MHz to 1.54MHz, what happens to the
propagation speed? - correct answer. remains the same
The units of PRF are: - correct answer. per minute
The time from the beginning of a pulse until its end is ______________? - correct
answer. pulsed duration
What happens to the speed of sound in a medium when the bulk modulus of the
medium increases? - correct answer. faster
___________ resolution is determined by SPL - correct answer. radial or axial
If a wave's amplitude is doubled, what happens to the power? - correct answer.
quadrupled
Power of sound has units of: - correct 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? - correct answer. halved
Which of these intensities is the smallest? SATP, SPTP, SATA - correct answer.
SATA
The duty factor for CW ultrasound is: - correct answer. 1.0
What is the minimum value of the duty factor? - correct answer. 0%
What are the units of intensity? - correct answer. watts/cm2
What happens to the speed of sound in a medium when the bulk modulus of the
medium decreases? - correct answer. slower
, 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 that? -
correct answer. 6 dB
The fundamental frequency of a transducer is 2.5 MHz. What is the second harmonic
frequency? - correct 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? -
correct answer. 10 cm
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the
longest wavelength? - correct answer. bone
If a 5 MHz sound wave is traveling in the tissues listed below, which will have the
shortest wavelength? - correct answer. air
What is the approximate attenuation coefficient of 1 MHz US in soft tissue? - correct
answer. .5 dB/cm
Rayl is the unit of: - correct answer. impedance
Impedance is the _________ of _________ and _________ - correct answer. product,
propagation speed, density
What are attenuation's three components? - correct answer. scattering, reflection,
absorption
For soft tissue, the approximate attenuation coefficient in dB/cm is equal to one-half
_________ in _________ - correct answer. frequency, MHz
As the impedance of two media become vastly different , the: - correct answer.
reflection increases
The angle between two media is 90 degrees. What is this called? - correct answer.
orthogonal incidence
The angle between two media is 56 degrees. This is called: - correct answer. oblique
incidence
Refraction only occurs if there are: - correct answer. oblique incidence and different
propagation speeds
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