ARDMS SPI Ultrasound Physics Certification
Test Study Questions and Answers | New 2026-
2027 Update
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - ANSWERS Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - ANSWERS 20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - ANSWERS Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - ANSWERS one complete
wavelength to pass a fixed point
PRP is determined by - ANSWERS Transmit time and receive time.
,Period is measured in - ANSWERS Time (μs)
When the sonographer changes the imaging depth what parameters are changed?
- ANSWERS PRP, PRF, Duty Factor
What is duty factor? - ANSWERS The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - ANSWERS 1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period -
ANSWERS Time, (μs)
Pulse duration is determined by - ANSWERS Sound Source Only
Pulse Duration is controlled by - ANSWERS the ultrasound system and
transducer
Pulse Duration Formula - ANSWERS pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
, Spatial Pulse Length (SPL) (measurement) - ANSWERS The distance that a
pulse occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - ANSWERS 0.1 to 1.0 mm
Spatial pulse length is determined by - ANSWERS sound source and medium
Spatial Pulse Length is directly proportional to - ANSWERS the Number of
Cycles in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - ANSWERS Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
Pulse Duration (PD) - ANSWERS The actual time from the start of a pulse to
the end of that pulse; a single transmit, talking, or "on" time.
Time the pulse is on typically measured in (ms).
Test Study Questions and Answers | New 2026-
2027 Update
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - ANSWERS Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - ANSWERS 20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - ANSWERS Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - ANSWERS one complete
wavelength to pass a fixed point
PRP is determined by - ANSWERS Transmit time and receive time.
,Period is measured in - ANSWERS Time (μs)
When the sonographer changes the imaging depth what parameters are changed?
- ANSWERS PRP, PRF, Duty Factor
What is duty factor? - ANSWERS The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - ANSWERS 1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period -
ANSWERS Time, (μs)
Pulse duration is determined by - ANSWERS Sound Source Only
Pulse Duration is controlled by - ANSWERS the ultrasound system and
transducer
Pulse Duration Formula - ANSWERS pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
, Spatial Pulse Length (SPL) (measurement) - ANSWERS The distance that a
pulse occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - ANSWERS 0.1 to 1.0 mm
Spatial pulse length is determined by - ANSWERS sound source and medium
Spatial Pulse Length is directly proportional to - ANSWERS the Number of
Cycles in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - ANSWERS Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
Pulse Duration (PD) - ANSWERS The actual time from the start of a pulse to
the end of that pulse; a single transmit, talking, or "on" time.
Time the pulse is on typically measured in (ms).
