Edelman's SPI Exam Tested
Questions With Revised Correct
Detailed Answers With Rationales
GRADED PASS
1) AMPLITUDE, POWER, & INTENSITY; What determines the initial amplitude of
an ultrasound wave?
A. the transducer
B. the medium through which the sound travels
C. both A and B
D. neither choice A nor B - ANSWER the transducer;
the initial strength or amplitude of a sound wave is determined by the vibration of
the piezoelectric crystal in the transducer. The greater the vibration of the crystal,
the larger the amplitude of the ultrasound wave.
2) AMPLITUDE, POWER, & INTENSITY; As an ultrasound wave travels through the
body, its amplitude usually:
A. decreases
B. increases
C. remains the same
D. cannot be determined - ANSWER decreases;
As a sound wave travels in the body, its
strength or amplitude diminishes. This
,process is called attenuation. We
experience attenuation when walking away
from a person who is speaking. The further
away we are from a speaker, the weaker
that person's voice becomes.
3) AMPLITUDE, POWER, & INTENSITY; T/F: A sonographer can routinely change
the power of a wave ultrasonic imaging. emitted by a transducer used in
diagnostic ultrasonic imaging. - ANSWER True. A sonographer can alter the
power of an
ultrasound wave by adjusting a control on
the ultrasound system. Power and amplitude are related; if the amplitude is
increased, then so is the power. When the amplitude decreases, the power also
decreases.
4) AMPLITUDE, POWER, & INTENSITY; Which of the following are acceptable units
for the amplitude of an acoustic
wave? (More than one answer may be correct.)
A. cm
B. pascals
C. gauss
D. watts - ANSWER A & B; cm, pascals
The acoustic variables are pressure, density, and particle motion. The units of
acoustic wave amplitude are cm for particle motion and pascals for pressure.
,AMPLITUDE, POWER, & INTENSITY; The maximum value of the density of an
acoustic wave is 60 lb/in^2 while the minimum density is 20 lb/in^2. What is the
amplitude of the wave?
A. 20 lb/in^2
B. 40 Ib/in^2
C. 60 lb/in2
D. none of the above - ANSWER 20 lb/in^2 ;
To calculate the amplitude of a wave,
subtract the minimum value of the acoustic variable from its maximum and then
divide that number in half. In this case, the maximum minus the minimum is 60-
20= 40 Ib/in^2. Half of 40 is 20 Ib/in^2
AMPLITUDE, POWER, & INTENSITY; The power of an ultrasound wave can be
reported with which of the following units? (More than one answer may be
correct.)
A. watts/square centimeter
B. dB/cm
C. watts
D. kg/cm^2 - ANSWER watts;
The units of power are watts. This is the
same measure of power as for light bulbs,
stereo systems, and curling irons.
AMPLITUDE, POWER, & INTENSITY; T/F: With standard diagnostic imaging
instrumentation, the sonographer has the ability to vary the amplitude of a sound
wave produced by the transducer. - ANSWER True. The sonographer can
adjust the strength of the ultrasound signal that a transducer creates. When a
, sonographer increases the output power, the electrical voltage sent to the
transducer is increased. This produces a more violent vibration of the
piezoelectric crystal within the transducer and, in turn, a stronger ultrasound
wave.
AMPLITUDE, POWER, & INTENSITY; Typically, as an ultrasound wave travels
through soft tissue, the power of the wave:
A. decreases
B. increases
C. remains the same - ANSWER decreases;
As a sound wave travels through the body, its power diminishes. This process is
called attenuation. Amplitude and power are both measures of the strength of an
acoustic wave, and tend to decrease as sound travels.
AMPLITUDE, POWER, & INTENSITY; Mathematically, when a number is squared,
the number is multiplied by:
A. 2
B. 0.5
C. itself
D. 1.5 - ANSWER itself;
To square a number means to multiply the
number by itself. Hence, the term "five
squared" means 5 times 5, or 25. Ten squared is 10 times 10, or 100.
AMPLITUDE, POWER, & INTENSITY; The final amplitude of an acoustic wave is
reduced to one-half of its original value. The final power is
the original power.
