SPI MOCK FINAL EXAM STUDY GUIDE
2026 COMPLETE QUESTIONS WITH
CORRECT DETAILED ANSWERS || 100%
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Section 1: Physics & Basic Principles (Questions 1-20)
1. What is the definition of sound?
A. The sensation of hearing
B. A mechanical, longitudinal wave that travels through a medium
C. An electromagnetic wave
D. A transverse wave
Answer: B. A mechanical, longitudinal wave that travels through a
medium
Detailed Explanation: Sound is a mechanical wave because it requires a medium
(solid, liquid, or gas) to propagate. It is longitudinal because the particle motion is
parallel to the direction of wave travel.
2. Which of the following is NOT an acoustic variable?
A. Pressure
B. Density
C. Temperature
D. Particle motion
Answer: C. Temperature
Detailed Explanation: Acoustic variables are parameters that change as a sound
wave passes through a medium. They are Pressure, Density, and Particle Motion.
Temperature is not considered a primary acoustic variable.
3. The number of cycles that occur in one second is defined as:
A. Wavelength
B. Period
,C. Frequency
D. Amplitude
Answer: C. Frequency
Detailed Explanation: Frequency (measured in Hertz, Hz) is the number of
complete cycles per second. It is determined by the sound source.
4. What is the typical value for the speed of sound in soft tissue?
A. 1,540 m/s
B. 1,000 m/s
C. 1,540 mm/µs
D. 3,000,000 m/s
Answer: A. 1,540 m/s
Detailed Explanation: While 1,540 m/s and 1.54 mm/µs are numerically similar,
the standard value used in clinical ultrasound is 1,540 meters per second.
5. If the frequency of a wave increases, what happens to the wavelength?
A. It increases
B. It decreases
C. It remains the same
D. It becomes zero
Answer: B. It decreases
Detailed Explanation: The relationship is governed by the formula: Speed =
Frequency × Wavelength. Since the speed in a given medium is relatively
constant, frequency and wavelength are inversely related.
6. Which of the following is determined by both the source and the medium?
A. Period
B. Frequency
C. Propagation Speed
D. Amplitude
Answer: C. Propagation Speed
Detailed Explanation: Propagation speed is primarily determined by the density
and stiffness (bulk modulus) of the medium. The source has no control over it once
the wave is generated.
,7. The time it takes for one cycle to occur is the:
A. Pulse Duration
B. Period
C. Spatial Pulse Length
D. Frequency
Answer: B. Period
Detailed Explanation: Period is the time from the start of one cycle to the start of
the next. It is the reciprocal of frequency (Period = 1 / Frequency).
8. What type of ultrasound intensity is most relevant to tissue heating?
A. Spatial Peak, Temporal Peak (SPTP)
B. Spatial Average, Temporal Average (SATA)
C. Spatial Peak, Pulse Average (SPPA)
D. Spatial Average, Pulse Average (SAPA)
Answer: B. Spatial Average, Temporal Average (SATA)
Detailed Explanation: SATA intensity considers the average intensity over both
space and time, making it the best indicator for the potential of bioeffects related to
heating (thermal effects).
9. The range of human hearing is approximately:
A. 2 Hz to 20,000 Hz
B. 20 Hz to 20,000 Hz
C. 2 MHz to 15 MHz
D. 20 kHz to 200 kHz
Answer: B. 20 Hz to 20,000 Hz
Detailed Explanation: Ultrasound, by definition, is sound with a frequency above
the range of human hearing, which is generally accepted as 20 Hz to 20,000 Hz.
10. Which of the following describes a wave's strength or the magnitude of its
acoustic variable?
A. Frequency
B. Wavelength
C. Amplitude
D. Power
, Answer: C. Amplitude
Detailed Explanation: Amplitude is the difference between the average value and
the maximum value of an acoustic variable. It is related to the "loudness" or
strength of the sound wave.
11. Power is defined as:
A. The distance a wave travels
B. The rate of energy transfer
C. The concentration of energy in a beam
D. The ability to do work
Answer: B. The rate of energy transfer
Detailed Explanation: Power is the rate at which work is performed or energy is
transferred. In ultrasound, it is measured in watts.
12. Intensity is best defined as:
A. The power of a wave
B. The speed of a wave
C. The concentration of energy in a beam
D. The frequency of a wave
Answer: C. The concentration of energy in a beam
Detailed Explanation: Intensity is the power of the wave divided by the cross-
sectional area of the beam (W/cm²). It describes how concentrated the energy is.
13. The duty factor for continuous wave ultrasound is:
A. 0
B. 0.5
C. 1
D. 100
Answer: C. 1
Detailed Explanation: Duty Factor is the fraction of time that the system is
transmitting sound. For Continuous Wave (CW) ultrasound, the system
is always transmitting, so the Duty Factor is 1 (or 100%).
14. If the amplitude of a wave is doubled, what happens to its power?
A. It doubles
2026 COMPLETE QUESTIONS WITH
CORRECT DETAILED ANSWERS || 100%
GUARANTEED PASS <RECENT
VERSION>
Section 1: Physics & Basic Principles (Questions 1-20)
1. What is the definition of sound?
A. The sensation of hearing
B. A mechanical, longitudinal wave that travels through a medium
C. An electromagnetic wave
D. A transverse wave
Answer: B. A mechanical, longitudinal wave that travels through a
medium
Detailed Explanation: Sound is a mechanical wave because it requires a medium
(solid, liquid, or gas) to propagate. It is longitudinal because the particle motion is
parallel to the direction of wave travel.
2. Which of the following is NOT an acoustic variable?
A. Pressure
B. Density
C. Temperature
D. Particle motion
Answer: C. Temperature
Detailed Explanation: Acoustic variables are parameters that change as a sound
wave passes through a medium. They are Pressure, Density, and Particle Motion.
Temperature is not considered a primary acoustic variable.
3. The number of cycles that occur in one second is defined as:
A. Wavelength
B. Period
,C. Frequency
D. Amplitude
Answer: C. Frequency
Detailed Explanation: Frequency (measured in Hertz, Hz) is the number of
complete cycles per second. It is determined by the sound source.
4. What is the typical value for the speed of sound in soft tissue?
A. 1,540 m/s
B. 1,000 m/s
C. 1,540 mm/µs
D. 3,000,000 m/s
Answer: A. 1,540 m/s
Detailed Explanation: While 1,540 m/s and 1.54 mm/µs are numerically similar,
the standard value used in clinical ultrasound is 1,540 meters per second.
5. If the frequency of a wave increases, what happens to the wavelength?
A. It increases
B. It decreases
C. It remains the same
D. It becomes zero
Answer: B. It decreases
Detailed Explanation: The relationship is governed by the formula: Speed =
Frequency × Wavelength. Since the speed in a given medium is relatively
constant, frequency and wavelength are inversely related.
6. Which of the following is determined by both the source and the medium?
A. Period
B. Frequency
C. Propagation Speed
D. Amplitude
Answer: C. Propagation Speed
Detailed Explanation: Propagation speed is primarily determined by the density
and stiffness (bulk modulus) of the medium. The source has no control over it once
the wave is generated.
,7. The time it takes for one cycle to occur is the:
A. Pulse Duration
B. Period
C. Spatial Pulse Length
D. Frequency
Answer: B. Period
Detailed Explanation: Period is the time from the start of one cycle to the start of
the next. It is the reciprocal of frequency (Period = 1 / Frequency).
8. What type of ultrasound intensity is most relevant to tissue heating?
A. Spatial Peak, Temporal Peak (SPTP)
B. Spatial Average, Temporal Average (SATA)
C. Spatial Peak, Pulse Average (SPPA)
D. Spatial Average, Pulse Average (SAPA)
Answer: B. Spatial Average, Temporal Average (SATA)
Detailed Explanation: SATA intensity considers the average intensity over both
space and time, making it the best indicator for the potential of bioeffects related to
heating (thermal effects).
9. The range of human hearing is approximately:
A. 2 Hz to 20,000 Hz
B. 20 Hz to 20,000 Hz
C. 2 MHz to 15 MHz
D. 20 kHz to 200 kHz
Answer: B. 20 Hz to 20,000 Hz
Detailed Explanation: Ultrasound, by definition, is sound with a frequency above
the range of human hearing, which is generally accepted as 20 Hz to 20,000 Hz.
10. Which of the following describes a wave's strength or the magnitude of its
acoustic variable?
A. Frequency
B. Wavelength
C. Amplitude
D. Power
, Answer: C. Amplitude
Detailed Explanation: Amplitude is the difference between the average value and
the maximum value of an acoustic variable. It is related to the "loudness" or
strength of the sound wave.
11. Power is defined as:
A. The distance a wave travels
B. The rate of energy transfer
C. The concentration of energy in a beam
D. The ability to do work
Answer: B. The rate of energy transfer
Detailed Explanation: Power is the rate at which work is performed or energy is
transferred. In ultrasound, it is measured in watts.
12. Intensity is best defined as:
A. The power of a wave
B. The speed of a wave
C. The concentration of energy in a beam
D. The frequency of a wave
Answer: C. The concentration of energy in a beam
Detailed Explanation: Intensity is the power of the wave divided by the cross-
sectional area of the beam (W/cm²). It describes how concentrated the energy is.
13. The duty factor for continuous wave ultrasound is:
A. 0
B. 0.5
C. 1
D. 100
Answer: C. 1
Detailed Explanation: Duty Factor is the fraction of time that the system is
transmitting sound. For Continuous Wave (CW) ultrasound, the system
is always transmitting, so the Duty Factor is 1 (or 100%).
14. If the amplitude of a wave is doubled, what happens to its power?
A. It doubles
