DMS 125 FINAL QUESTIONS WITH COMPLETE
SOLUTIONS
-3dB means Correct Answers 1/2 intensity
1MHz wavelength= Correct Answers 1.54mm
3 basic modes of display in viewing ultrasound are Correct
Answers A-mode, B-mode, M-mode
A damaged active element on this transducer would cause a
section of the image directly below the damaged element to be
missing Correct Answers Linear sequential array
A reduction in the intensity of a sound beam to one-half its
original value is _____ dB Correct Answers -3dB
A sonographer is performing a study on a patient and desires
superior depth resolution Which of the following changes would
create such a system?
A. higher frequency
B. shorter wavelength
C. fewer cycles per pulse
D. less ringing
E. all of the above Correct Answers All of the above
A sound wave reaches a rough or irregular border between two
media. Under these circumstances which process is most likely
to occur? Correct Answers Backscatter reflection
,A sound wave strikes a boundary at normal incidence. The
impedances of the two media are identical. What percentage of
the sound wave is reflected? Correct Answers 0%
Acoustic propagation properties are Correct Answers The
effects of the medium upon the sound wave
Acoustic variable properties are Correct Answers Distance,
pressure, density
All elements of this transducer are fired at the same time to
create each sound beam Correct Answers Linear sequential
array
An interaction of echoes that leads to reinforcement rather than a
partial or total cancellation is known as Correct Answers
constructive interference
An original intensity of a sound beam is 2 watts with a beam
area of 2cm^2. What is the intensity if the beam area changes to
4cm^2? Correct Answers It halved
An ultrasonic pulse has a pulse repetition period of 1.2 msec, a
spatial pulse length of 2.0 mm, and a wavelength of 0.4 mm.
What is the axial resolution of the system? Correct Answers 1.0
mm
As a general rule, which of the following lists media in
increasing (slow to fast) order of propagation speeds? Correct
Answers Gas, liquid, solid
, As sound propagates through a medium, the total power in the
wave decreases. What is this process called? Correct Answers
Attenuation
Assume that the frequency of a sound with the greatest power
emitted by the transducer is 9Mhz. However, the transducer
produces acoustic energy with frequencies as low as 6.5Mhz and
as high as 12.5Mhz. What is the quality factor of the transducer?
Correct Answers 9/6
Attenuation coefficient= Correct Answers .5dB/cm/MHz
Attenuation is determined by 2 factors, what are they? Correct
Answers Frequency and path length
Axial resolution Correct Answers
Axial resolution is determined only by the components of the
system (T/F) Correct Answers False
Axial resolution is measured parallel to the sound beam's main
axis (T/F) Correct Answers True
Axial resolution= Correct Answers .77 x #cycles in
pulse/frequency(MHz)
By adjusting the imaging depth, the sonographer changes the
Correct Answers Pulse repetition period, duty factor, and pulse
repetition frequency
SOLUTIONS
-3dB means Correct Answers 1/2 intensity
1MHz wavelength= Correct Answers 1.54mm
3 basic modes of display in viewing ultrasound are Correct
Answers A-mode, B-mode, M-mode
A damaged active element on this transducer would cause a
section of the image directly below the damaged element to be
missing Correct Answers Linear sequential array
A reduction in the intensity of a sound beam to one-half its
original value is _____ dB Correct Answers -3dB
A sonographer is performing a study on a patient and desires
superior depth resolution Which of the following changes would
create such a system?
A. higher frequency
B. shorter wavelength
C. fewer cycles per pulse
D. less ringing
E. all of the above Correct Answers All of the above
A sound wave reaches a rough or irregular border between two
media. Under these circumstances which process is most likely
to occur? Correct Answers Backscatter reflection
,A sound wave strikes a boundary at normal incidence. The
impedances of the two media are identical. What percentage of
the sound wave is reflected? Correct Answers 0%
Acoustic propagation properties are Correct Answers The
effects of the medium upon the sound wave
Acoustic variable properties are Correct Answers Distance,
pressure, density
All elements of this transducer are fired at the same time to
create each sound beam Correct Answers Linear sequential
array
An interaction of echoes that leads to reinforcement rather than a
partial or total cancellation is known as Correct Answers
constructive interference
An original intensity of a sound beam is 2 watts with a beam
area of 2cm^2. What is the intensity if the beam area changes to
4cm^2? Correct Answers It halved
An ultrasonic pulse has a pulse repetition period of 1.2 msec, a
spatial pulse length of 2.0 mm, and a wavelength of 0.4 mm.
What is the axial resolution of the system? Correct Answers 1.0
mm
As a general rule, which of the following lists media in
increasing (slow to fast) order of propagation speeds? Correct
Answers Gas, liquid, solid
, As sound propagates through a medium, the total power in the
wave decreases. What is this process called? Correct Answers
Attenuation
Assume that the frequency of a sound with the greatest power
emitted by the transducer is 9Mhz. However, the transducer
produces acoustic energy with frequencies as low as 6.5Mhz and
as high as 12.5Mhz. What is the quality factor of the transducer?
Correct Answers 9/6
Attenuation coefficient= Correct Answers .5dB/cm/MHz
Attenuation is determined by 2 factors, what are they? Correct
Answers Frequency and path length
Axial resolution Correct Answers
Axial resolution is determined only by the components of the
system (T/F) Correct Answers False
Axial resolution is measured parallel to the sound beam's main
axis (T/F) Correct Answers True
Axial resolution= Correct Answers .77 x #cycles in
pulse/frequency(MHz)
By adjusting the imaging depth, the sonographer changes the
Correct Answers Pulse repetition period, duty factor, and pulse
repetition frequency
