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: c b a
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