ARDMS SPI STUDY GUIDE South College
Pathophysiology Exam 2 Verified
Questions and Answers Study Guide 2026
Latest 2026/2027 | A+ Graded | 100 %
Guaranteed Pass
Question
In soft tissue, if the frequency of a wave is increased, the propagation speed will:
A) Increase
B) Decrease
C) Remain the same because stiffness and density affect propagation speed
D) Double
Expert Rationale: Propagation speed in soft tissue is determined by the stiffness and
density of the medium, not by frequency. In soft tissue, propagation speed remains
constant at 1,540 m/s regardless of frequency changes. Stiffness and density are the only
factors that affect propagation speed.
Question
What is the audible range for sound?
A) 1-20 MHz
B) 20-20,000 Hz
C) 2-10 MHz
D) 20,000-20,000,000 Hz
Expert Rationale: The audible range for sound is 20-20,000 Hz. Sound above 20,000 Hz is
ultrasound. Diagnostic ultrasound typically uses frequencies of 1-20 MHz.
Question
What is the unit of measurement for frequency?
,A) Meters (m)
B) Hertz (Hz)
C) Decibels (dB)
D) Pascals (Pa)
Expert Rationale: Frequency is measured in Hertz (Hz), which is cycles per second. It is
not affected by the sonographer. Increasing frequency decreases depth of penetration.
Question
A period is the length of time it takes for:
A) One complete wavelength to pass a fixed point
B) The pulse to travel to the reflector and back
C) The transducer to fire
D) The sound beam to attenuate
Expert Rationale: A period is the length of time it takes for one complete wavelength to
pass a fixed point. It is measured in time (μs) and is determined by the sound source.
Question
PRP (Pulse Repetition Period) is determined by:
A) Frequency and wavelength
B) Transmit time and receive time
C) Amplitude and intensity
D) Density and stiffness
Expert Rationale: PRP (Pulse Repetition Period) is determined by transmit time and receive
time. It is the time from the start of one pulse to the start of the next pulse. It is measured in
time (μs).
Question
Period is measured in:
A) Millimeters (mm)
B) Hertz (Hz)
C) Time (μs)
D) Decibels (dB)
,Expert Rationale: Period is measured in time (μs). It is the time it takes for one complete
wavelength to pass a fixed point. It is determined by the sound source only.
Question
When the sonographer changes the imaging depth, which parameters are changed?
A) PRP, PRF, Duty Factor
B) Frequency, Wavelength, Period
C) Amplitude, Intensity, Power
D) Density, Stiffness, Impedance
Expert Rationale: When the sonographer changes the imaging depth, PRP (Pulse
Repetition Period), PRF (Pulse Repetition Frequency), and Duty Factor are changed. These
parameters are affected by depth because deeper imaging requires more time between
pulses.
Question
What is duty factor?
A) The percentage or fraction of time that the system is transmitting a pulse
B) The time it takes for one wavelength to pass
C) The distance of one pulse
D) The frequency of the transducer
Expert Rationale: Duty factor is the percentage or fraction of time that the system is
transmitting a pulse (time sound is ON or ON-time). It is unitless and has a maximum value
of 1 and a minimum of 0.
Question
What is the propagation speed in soft tissue?
A) 1,540 m/s (1.54 mm/μs)
B) 330 m/s
C) 4,080 m/s
D) 1,450 m/s
Expert Rationale: The propagation speed in soft tissue is 1,540 m/s or 1.54 mm/μs. This is
a constant value in soft tissue and is determined by stiffness and density.
, Question
What is the unit of measurement for pulse duration, duty factor, PRP, and period?
A) Millimeters (mm)
B) Time (μs)
C) Hertz (Hz)
D) Decibels (dB)
Expert Rationale: The unit of measurement for pulse duration, PRP, and period is time (μs).
Duty factor is unitless. Pulse duration is the actual time from the start of a pulse to the end
of that pulse.
Question
Pulse duration is determined by:
A) Sound source only
B) Medium only
C) Both sound source and medium
D) The sonographer
Expert Rationale: Pulse duration is determined by the sound source only. It is controlled by
the ultrasound system and transducer. It is the actual time from the start of a pulse to the
end of that pulse.
Question
What is the formula for pulse duration?
A) PD = number of cycles in pulse / frequency
B) PD = wavelength / frequency
C) PD = frequency × wavelength
D) PD = propagation speed / frequency
Expert Rationale: The formula for pulse duration is PD = number of cycles in pulse /
frequency. It is measured in time (μs). Pulse duration is determined by the sound source
only.
Pathophysiology Exam 2 Verified
Questions and Answers Study Guide 2026
Latest 2026/2027 | A+ Graded | 100 %
Guaranteed Pass
Question
In soft tissue, if the frequency of a wave is increased, the propagation speed will:
A) Increase
B) Decrease
C) Remain the same because stiffness and density affect propagation speed
D) Double
Expert Rationale: Propagation speed in soft tissue is determined by the stiffness and
density of the medium, not by frequency. In soft tissue, propagation speed remains
constant at 1,540 m/s regardless of frequency changes. Stiffness and density are the only
factors that affect propagation speed.
Question
What is the audible range for sound?
A) 1-20 MHz
B) 20-20,000 Hz
C) 2-10 MHz
D) 20,000-20,000,000 Hz
Expert Rationale: The audible range for sound is 20-20,000 Hz. Sound above 20,000 Hz is
ultrasound. Diagnostic ultrasound typically uses frequencies of 1-20 MHz.
Question
What is the unit of measurement for frequency?
,A) Meters (m)
B) Hertz (Hz)
C) Decibels (dB)
D) Pascals (Pa)
Expert Rationale: Frequency is measured in Hertz (Hz), which is cycles per second. It is
not affected by the sonographer. Increasing frequency decreases depth of penetration.
Question
A period is the length of time it takes for:
A) One complete wavelength to pass a fixed point
B) The pulse to travel to the reflector and back
C) The transducer to fire
D) The sound beam to attenuate
Expert Rationale: A period is the length of time it takes for one complete wavelength to
pass a fixed point. It is measured in time (μs) and is determined by the sound source.
Question
PRP (Pulse Repetition Period) is determined by:
A) Frequency and wavelength
B) Transmit time and receive time
C) Amplitude and intensity
D) Density and stiffness
Expert Rationale: PRP (Pulse Repetition Period) is determined by transmit time and receive
time. It is the time from the start of one pulse to the start of the next pulse. It is measured in
time (μs).
Question
Period is measured in:
A) Millimeters (mm)
B) Hertz (Hz)
C) Time (μs)
D) Decibels (dB)
,Expert Rationale: Period is measured in time (μs). It is the time it takes for one complete
wavelength to pass a fixed point. It is determined by the sound source only.
Question
When the sonographer changes the imaging depth, which parameters are changed?
A) PRP, PRF, Duty Factor
B) Frequency, Wavelength, Period
C) Amplitude, Intensity, Power
D) Density, Stiffness, Impedance
Expert Rationale: When the sonographer changes the imaging depth, PRP (Pulse
Repetition Period), PRF (Pulse Repetition Frequency), and Duty Factor are changed. These
parameters are affected by depth because deeper imaging requires more time between
pulses.
Question
What is duty factor?
A) The percentage or fraction of time that the system is transmitting a pulse
B) The time it takes for one wavelength to pass
C) The distance of one pulse
D) The frequency of the transducer
Expert Rationale: Duty factor is the percentage or fraction of time that the system is
transmitting a pulse (time sound is ON or ON-time). It is unitless and has a maximum value
of 1 and a minimum of 0.
Question
What is the propagation speed in soft tissue?
A) 1,540 m/s (1.54 mm/μs)
B) 330 m/s
C) 4,080 m/s
D) 1,450 m/s
Expert Rationale: The propagation speed in soft tissue is 1,540 m/s or 1.54 mm/μs. This is
a constant value in soft tissue and is determined by stiffness and density.
, Question
What is the unit of measurement for pulse duration, duty factor, PRP, and period?
A) Millimeters (mm)
B) Time (μs)
C) Hertz (Hz)
D) Decibels (dB)
Expert Rationale: The unit of measurement for pulse duration, PRP, and period is time (μs).
Duty factor is unitless. Pulse duration is the actual time from the start of a pulse to the end
of that pulse.
Question
Pulse duration is determined by:
A) Sound source only
B) Medium only
C) Both sound source and medium
D) The sonographer
Expert Rationale: Pulse duration is determined by the sound source only. It is controlled by
the ultrasound system and transducer. It is the actual time from the start of a pulse to the
end of that pulse.
Question
What is the formula for pulse duration?
A) PD = number of cycles in pulse / frequency
B) PD = wavelength / frequency
C) PD = frequency × wavelength
D) PD = propagation speed / frequency
Expert Rationale: The formula for pulse duration is PD = number of cycles in pulse /
frequency. It is measured in time (μs). Pulse duration is determined by the sound source
only.
