1|Page
SPI EXAM NEWEST 2026-2027 COMPLETE ALL
QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES (VERIFIED ANSWERS) |ALREADY
GRADED A+
69. Which of the following has time represented on the X-
axis?
a. B mode
b. X-mode
c. M mode
d. A mode - ANSWER-C. M-Mode has depth on the y-axis
and time on the x-axis
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28. The density is the same in materials A and B, but the
speed of sound in material B is 10% greater than the
speed of sound in material A.
a. The acoustic impedance in B is 10% greater than the
acoustic impedance in A
b. The sound velocity in A is 10% higher than the
propagation speed in B
c. The acoustic impedance in A is equal to the acoustic
impedance in B
d. The acoustic impedance in A is 10% higher than the
acoustic impedance in B - ANSWER-A. Impedance =
density x propagation speed (z=ρc). If the density of the
two materials is unchanged, but the speed of sound is
10% higher in medium 2, then it must be because the
impedance is 10% higher in medium 2.
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29. Matching layers in a transducer
a. improve axial resolution
b. provide damping
c. determine the operating frequency
d. provide greater efficiency of sound transmission from
the transducer to the patient - ANSWER-D. The matching
layers decrease the differences in impedances between
the element and the skin, thereby improving the efficiency
of sound transmission into the patient
30. The acoustic impedance of a matching layer in a
transducer should have a value
, 4|Page
a. between the acoustic impedance of the piezoelectric
element and the acoustic impedance of tissue
b. lower than the acoustic impedance of tissue
c. greater than the acoustic impedance of the piezoelectric
element
d. equal to the acoustic impedance of the piezoelectric
element - ANSWER-A. In order to decrease reflection
between the element and the skin, the impedance of the
matching layer must be between that of the element and
the skin. (Remember: reflection is caused by an
impedance mismatch)
31. The prefix micro- represents the mathematical value
a. 10^6
SPI EXAM NEWEST 2026-2027 COMPLETE ALL
QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES (VERIFIED ANSWERS) |ALREADY
GRADED A+
69. Which of the following has time represented on the X-
axis?
a. B mode
b. X-mode
c. M mode
d. A mode - ANSWER-C. M-Mode has depth on the y-axis
and time on the x-axis
,2|Page
28. The density is the same in materials A and B, but the
speed of sound in material B is 10% greater than the
speed of sound in material A.
a. The acoustic impedance in B is 10% greater than the
acoustic impedance in A
b. The sound velocity in A is 10% higher than the
propagation speed in B
c. The acoustic impedance in A is equal to the acoustic
impedance in B
d. The acoustic impedance in A is 10% higher than the
acoustic impedance in B - ANSWER-A. Impedance =
density x propagation speed (z=ρc). If the density of the
two materials is unchanged, but the speed of sound is
10% higher in medium 2, then it must be because the
impedance is 10% higher in medium 2.
,3|Page
29. Matching layers in a transducer
a. improve axial resolution
b. provide damping
c. determine the operating frequency
d. provide greater efficiency of sound transmission from
the transducer to the patient - ANSWER-D. The matching
layers decrease the differences in impedances between
the element and the skin, thereby improving the efficiency
of sound transmission into the patient
30. The acoustic impedance of a matching layer in a
transducer should have a value
, 4|Page
a. between the acoustic impedance of the piezoelectric
element and the acoustic impedance of tissue
b. lower than the acoustic impedance of tissue
c. greater than the acoustic impedance of the piezoelectric
element
d. equal to the acoustic impedance of the piezoelectric
element - ANSWER-A. In order to decrease reflection
between the element and the skin, the impedance of the
matching layer must be between that of the element and
the skin. (Remember: reflection is caused by an
impedance mismatch)
31. The prefix micro- represents the mathematical value
a. 10^6
