Sound waves are:
a) electric
b) mechanical, transverse
c) spectral
d) longitudinal, mechanical - ANS D
The speed of sound of ultrasound in soft tissue is closest to:
a) 1,540 km/sec
b) 1.54 km/sec
c) 1,500 m/s
d) 1,540 mm/sec - ANS C
Which is not an acoustic vari...
Sound waves are:
a) electric
b) mechanical, transverse
c) spectral
d) longitudinal, mechanical - ANS D
The speed of sound of ultrasound in soft tissue is closest to:
a) 1,540 km/sec
b) 1.54 km/sec
c) 1,500 m/s
d) 1,540 mm/sec - ANS C
Which is not an acoustic variable?
a) density
b) pressure
c) distance
d) intensity - ANS D
The effects of soft tissue on ultrasound are called:
a) acoustic proliferation properties
b) dynamic effects
c) acoustic propagation properties
d) biological effects - ANS C
All of the following are true EXCEPT:
a) two waves with identical frequencies must interfere constructively.
b) constructive interference is associated with waves that are in-phase.
c) out-of-phase waves interfere destructively.
d) waves of different frequencies may exhibit both constructive and destructive interference at
different times. - ANS A
Put in decreasing order:
a) deca
b) deci
c) micro
,d) centi - ANS abdc
______ is the time to complete one cycle
a) pulse duration
b) pulse period
c) period
d) duration period - ANS C
Which of the following sound waves is ultrasonic and least useful in diagnostic imaging?
a) 30 KHz
b) 8 Mhz
c) 8,000 Hz
d) 3,000 Hz
e) 15 Hz - ANS A
______ is the distance covered by one cycle.
a) pulse length
b) wavelength
c) cycle distance
d) cycle duration - ANS B
Which of the following is determined by the source and the medium?
a) frequency
b) period
c) propagation speed
d) range resolution - ANS D
Propagation speed = _______ x wavelength
a) pulse duration
b) period
c) # of cycles in the pulse
d) frequency - ANS D
As a result of _____ the propagation speed increases.
a) increasing stiffness and increasing density
b) increasing stiffness and increasing elasticity
c) decreasing compressibility and decreasing density
d) decreasing stiffness and decreasing density. - ANS C
Put in decreasing order of propagation speed.
a) gas
b) liquid
c) solid - ANS cba
,If the frequency of an ultrasound wave is doubled, what happens to the period?
a) doubles
b) halved
c) remains the same
d) 4x greater - ANS B
The units of pulse repetition frequency are:
a) per minute
b) microseconds
c) mm/microseconds
d) MHz - ANS A
The time from the beginning of the pulse to the end of that pulse is _______?
a) period
b) pulse duration
c) pulse length
d) PRF - ANS B
What happens to the speed of sound in a medium when the bulk modulus increases?
a) faster
b) slower
c) unchanged - ANS A
_________ resolution is determined by the spatial pulse length
a) radial
b) image
c) axial
d) angular - ANS A or C
If the wave's amplitude is doubles, what happens to the power?
a) nothing
b) halved
c) doubled
d) quadrupled - ANS D
If the level of acoustic variable ranges from 55-105, what is the amplitude?
a) 105
b) 50
c) 25
d) 55 - ANS 25
Power of sound has units of:
a) dB
b) dB/cm
, c) watts
d) watts/cm^2 - ANS C
If the intensity of a sound beam remains unchanged while the beam area is reduced in half,
what has happened to the power?
a) quadrupled
b) doubled
c) halved
d) unchanged - ANS C
Which of these intensities is the smallest?
a) SATP
b) SPTP
c) SATA - ANS C
The duty factor for CW ultrasound is
a) 10.0
b) 1%
c) 1.0
d) 0.0% - ANS C
What is the minimum value of the duty factor? a) 10.0
b) 1%
c) 1.0
d) 0.0% - ANS D
What are the units of intensity?
a) watts
b) dB
c) watts/cm^2
d) dB - ANS C
What happens to the speed of sound in a medium when the bulk modulus of the medium
decreases?
a) faster
b) slower
d) unchanged - ANS B
The units of attenuation are ___ : this is a ___ scale
A) mm/cm ; parametric
B) dB/m ; multiplicative
C) none ; relative
D) dB ; logarithmic - ANS D
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