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EDELMAN'S SPI REVIEW EXAM LATEST VERSION QUESTIONS
AND ANSWERS 2026 EDITION
Edelman's SPI Exam Review: 250 Practice Questions with Rationales
DOMAIN 1: PHYSICAL PRINCIPLES (50 Questions)
1. The vertical axis of a graph is called the:
A) X-axis
B) Y-axis
C) Z-axis
D) Time-axis
Answer: B) Y-axis
Rationale: The vertical axis of a graph is the y-axis, extending up and down. The
horizontal axis is the x-axis, extending side to side .
2. The speed of sound in soft tissue is closest to:
A) 1,540 m/sec
B) 1,540 km/sec
C) 1,540 mm/sec
D) 1,540 cm/sec
Answer: A) 1,540 m/sec
Rationale: The average propagation speed of sound in soft tissue is approximately 1,540
m/sec. This is a fundamental constant used in ultrasound imaging for depth calibration .
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3. What is the round-trip travel time per centimeter in soft tissue?
A) 6.5 microseconds
B) 13 microseconds
C) 26 microseconds
D) 52 microseconds
Answer: B) 13 microseconds
Rationale: The round-trip travel time per centimeter in soft tissue is 13 microseconds.
The "13 microsecond rule" is used to convert time-of-flight information to depth. For
every 1 cm of depth, sound travels 2 cm round trip at 1,540 m/sec .
4. Which of the following is NOT a characteristic of sound waves?
A) They are longitudinal waves
B) They are mechanical waves
C) They travel through a vacuum
D) They require a medium
Answer: C) They travel through a vacuum
Rationale: Sound waves are mechanical and longitudinal waves that require a medium
to propagate. They cannot travel through a vacuum. Electromagnetic waves (light, X-
rays) can travel through a vacuum .
5. The distance covered by one cycle of a sound wave is called the:
A) Period
B) Wavelength
C) Amplitude
D) Frequency
Answer: B) Wavelength
Rationale: Wavelength is the distance over which one complete cycle of a wave occurs.
It is determined by both the source (frequency) and the medium (propagation speed).
The relationship is: wavelength = propagation speed ÷ frequency .
6. The time required to complete one cycle of a sound wave is called the:
A) Wavelength
B) Period
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C) Frequency
D) Amplitude
Answer: B) Period
Rationale: The period is the time required to complete one cycle. It is the reciprocal of
frequency. Period = 1/frequency. The units of period are time (microseconds,
milliseconds) .
7. What is the frequency of a wave with a 1 msec period?
A) 1 Hz
B) 10 Hz
C) 100 Hz
D) 1,000 Hz (1 kHz)
Answer: D) 1,000 Hz (1 kHz)
Rationale: Period and frequency are reciprocals. If the period is 1 msec (0.001 sec), then
frequency = 1/0.001 = 1,000 Hz or 1 kHz .
8. Which of the following sound waves is ultrasonic but LEAST useful in diagnostic
imaging?
A) 2 MHz
B) 5 MHz
C) 7.5 MHz
D) 30 kHz
Answer: D) 30 kHz
Rationale: Ultrasound frequencies used in diagnostic imaging typically range from 2
MHz to 15 MHz. A 30 kHz wave is below the audible range of humans but is considered
ultrasound. However, it is too low frequency to provide adequate resolution for
diagnostic imaging .
9. A sound wave with a frequency of 5 MHz has a period of:
A) 0.2 microseconds
B) 0.5 microseconds
C) 2.0 microseconds
D) 5.0 microseconds
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Answer: A) 0.2 microseconds
Rationale: Period = 1/frequency = 1/5 MHz = 0.2 microseconds. For reference, a 2 MHz
wave has a period of 0.5 microseconds .
10. What is the range of periods commonly found in diagnostic ultrasound waves?
A) 0.006 to 0.05 microseconds
B) 0.06 to 0.5 microseconds
C) 0.6 to 5.0 microseconds
D) 6.0 to 50 microseconds
Answer: B) 0.06 to 0.5 microseconds
Rationale: Diagnostic ultrasound frequencies range from about 2 MHz to 15 MHz. Period
is the reciprocal of frequency, so for 2 MHz (period = 0.5 μs) to 15 MHz (period = 0.06
μs) .
11. The amplitude of a sound wave is decreased to one-half of its original value.
What happens to the power?
A) It remains the same
B) It is halved
C) It is reduced to one-quarter
D) It is doubled
Answer: C) It is reduced to one-quarter
Rationale: Power is proportional to amplitude squared. If amplitude is reduced by 1/2,
power is reduced by (1/2)² = 1/4 of its original value .
12. The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If
the initial power was 27 watts, what is the final power?
A) 3 watts
B) 9 watts
C) 27 watts
D) 81 watts
Answer: A) 3 watts
EDELMAN'S SPI REVIEW EXAM LATEST VERSION QUESTIONS
AND ANSWERS 2026 EDITION
Edelman's SPI Exam Review: 250 Practice Questions with Rationales
DOMAIN 1: PHYSICAL PRINCIPLES (50 Questions)
1. The vertical axis of a graph is called the:
A) X-axis
B) Y-axis
C) Z-axis
D) Time-axis
Answer: B) Y-axis
Rationale: The vertical axis of a graph is the y-axis, extending up and down. The
horizontal axis is the x-axis, extending side to side .
2. The speed of sound in soft tissue is closest to:
A) 1,540 m/sec
B) 1,540 km/sec
C) 1,540 mm/sec
D) 1,540 cm/sec
Answer: A) 1,540 m/sec
Rationale: The average propagation speed of sound in soft tissue is approximately 1,540
m/sec. This is a fundamental constant used in ultrasound imaging for depth calibration .
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3. What is the round-trip travel time per centimeter in soft tissue?
A) 6.5 microseconds
B) 13 microseconds
C) 26 microseconds
D) 52 microseconds
Answer: B) 13 microseconds
Rationale: The round-trip travel time per centimeter in soft tissue is 13 microseconds.
The "13 microsecond rule" is used to convert time-of-flight information to depth. For
every 1 cm of depth, sound travels 2 cm round trip at 1,540 m/sec .
4. Which of the following is NOT a characteristic of sound waves?
A) They are longitudinal waves
B) They are mechanical waves
C) They travel through a vacuum
D) They require a medium
Answer: C) They travel through a vacuum
Rationale: Sound waves are mechanical and longitudinal waves that require a medium
to propagate. They cannot travel through a vacuum. Electromagnetic waves (light, X-
rays) can travel through a vacuum .
5. The distance covered by one cycle of a sound wave is called the:
A) Period
B) Wavelength
C) Amplitude
D) Frequency
Answer: B) Wavelength
Rationale: Wavelength is the distance over which one complete cycle of a wave occurs.
It is determined by both the source (frequency) and the medium (propagation speed).
The relationship is: wavelength = propagation speed ÷ frequency .
6. The time required to complete one cycle of a sound wave is called the:
A) Wavelength
B) Period
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C) Frequency
D) Amplitude
Answer: B) Period
Rationale: The period is the time required to complete one cycle. It is the reciprocal of
frequency. Period = 1/frequency. The units of period are time (microseconds,
milliseconds) .
7. What is the frequency of a wave with a 1 msec period?
A) 1 Hz
B) 10 Hz
C) 100 Hz
D) 1,000 Hz (1 kHz)
Answer: D) 1,000 Hz (1 kHz)
Rationale: Period and frequency are reciprocals. If the period is 1 msec (0.001 sec), then
frequency = 1/0.001 = 1,000 Hz or 1 kHz .
8. Which of the following sound waves is ultrasonic but LEAST useful in diagnostic
imaging?
A) 2 MHz
B) 5 MHz
C) 7.5 MHz
D) 30 kHz
Answer: D) 30 kHz
Rationale: Ultrasound frequencies used in diagnostic imaging typically range from 2
MHz to 15 MHz. A 30 kHz wave is below the audible range of humans but is considered
ultrasound. However, it is too low frequency to provide adequate resolution for
diagnostic imaging .
9. A sound wave with a frequency of 5 MHz has a period of:
A) 0.2 microseconds
B) 0.5 microseconds
C) 2.0 microseconds
D) 5.0 microseconds
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Answer: A) 0.2 microseconds
Rationale: Period = 1/frequency = 1/5 MHz = 0.2 microseconds. For reference, a 2 MHz
wave has a period of 0.5 microseconds .
10. What is the range of periods commonly found in diagnostic ultrasound waves?
A) 0.006 to 0.05 microseconds
B) 0.06 to 0.5 microseconds
C) 0.6 to 5.0 microseconds
D) 6.0 to 50 microseconds
Answer: B) 0.06 to 0.5 microseconds
Rationale: Diagnostic ultrasound frequencies range from about 2 MHz to 15 MHz. Period
is the reciprocal of frequency, so for 2 MHz (period = 0.5 μs) to 15 MHz (period = 0.06
μs) .
11. The amplitude of a sound wave is decreased to one-half of its original value.
What happens to the power?
A) It remains the same
B) It is halved
C) It is reduced to one-quarter
D) It is doubled
Answer: C) It is reduced to one-quarter
Rationale: Power is proportional to amplitude squared. If amplitude is reduced by 1/2,
power is reduced by (1/2)² = 1/4 of its original value .
12. The amplitude of an acoustic wave decreases from 27 pascals to 9 pascals. If
the initial power was 27 watts, what is the final power?
A) 3 watts
B) 9 watts
C) 27 watts
D) 81 watts
Answer: A) 3 watts
