1|Page
NRRPT PREP COMPLETE STUDY GUIDE EXAM LATEST
2026/2027 UPDATED VERIFIED QUESTIONS AND
SOLUTIONS A+ PASS GUARANTEED
Question Number: 1
Fundamentals of Radiation Protection
A low energy alpha detector is usually effective if the detector is distant
from the source.
A) 1/4 inch
B) 1/2 inch
C) 1 inch
D) 1 1/2 inches
E) 2 inches ......ANSWER......The correct answer is: A
Low energy alpha particles can only travel less than 1/2 inch in air.
Therefore, one must be closer than this to detect them.
Question Number: 2
Fundamentals of Radiation Protection
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A sample of I-131 (half life = 8 days) is kept for 80 days, at which time
the activity is 1 µCi . What was the original activity?
A) 2.0 mCi
B) 1.0 mCi
C) 1.5 mCi
D) 3.5 mCi
E) 4.0 mCi ......ANSWER......The correct answer is: B
After 10 half lives, the remaining activity is approximately 1000th of the
original amount. Therefore, if there was 1µCi left after 10 half lives,
then there must have been 1000 times more to start with. Hence, 1 µCi
* 1000 = 1 mCi.
Question Number: 3
Fundamentals of Radiation Protection
A sample of radioactive material is reported to contain 2000 picocuries
of activity. Express this value as disintegrations per minute.
A) 370 dpm
B) 900 dpm
C) 3770 dpm
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D) 4440 dpm
E) 5320 dpm ......ANSWER......The correct answer is: D
dps = (2000 pCi)(1 x 10-12Ci/pi )(3.7x1010 dps/Ci) dps = 74
dpm = (74 dps) (60 sec/min)
dpm = 4440
Remember to convert to disintegrations per minute not
DISINTEGRATIONS PER SECOND.
Question Number: 1
Fundamentals of Radiation Protection
A low energy alpha detector is usually effective if the detector is distant
from the source.
A) 1/4 inch
B) 1/2 inch
C) 1 inch
D) 1 1/2 inches
E) 2 inches ......ANSWER......The correct answer is: A
Low energy alpha particles can only travel less than 1/2 inch in air.
Therefore, one must be closer than this to detect them.
, 4|Page
Question Number: 2
Fundamentals of Radiation Protection
A sample of I-131 (half life = 8 days) is kept for 80 days, at which time
the activity is 1 µCi . What was the original activity?
A) 2.0 mCi
B) 1.0 mCi
C) 1.5 mCi
D) 3.5 mCi
E) 4.0 mCi ......ANSWER......The correct answer is: B
After 10 half lives, the remaining activity is approximately 1000th of the
original amount. Therefore, if there was 1
µCi left after 10 half lives, then there must have been 1000 times more
to start with. Hence, 1 µCi * 1000 = 1 mCi.
Question Number: 3
Fundamentals of Radiation Protection
A sample of radioactive material is reported to contain 2000 picocuries
of activity. Express this value as
NRRPT PREP COMPLETE STUDY GUIDE EXAM LATEST
2026/2027 UPDATED VERIFIED QUESTIONS AND
SOLUTIONS A+ PASS GUARANTEED
Question Number: 1
Fundamentals of Radiation Protection
A low energy alpha detector is usually effective if the detector is distant
from the source.
A) 1/4 inch
B) 1/2 inch
C) 1 inch
D) 1 1/2 inches
E) 2 inches ......ANSWER......The correct answer is: A
Low energy alpha particles can only travel less than 1/2 inch in air.
Therefore, one must be closer than this to detect them.
Question Number: 2
Fundamentals of Radiation Protection
,2|Page
A sample of I-131 (half life = 8 days) is kept for 80 days, at which time
the activity is 1 µCi . What was the original activity?
A) 2.0 mCi
B) 1.0 mCi
C) 1.5 mCi
D) 3.5 mCi
E) 4.0 mCi ......ANSWER......The correct answer is: B
After 10 half lives, the remaining activity is approximately 1000th of the
original amount. Therefore, if there was 1µCi left after 10 half lives,
then there must have been 1000 times more to start with. Hence, 1 µCi
* 1000 = 1 mCi.
Question Number: 3
Fundamentals of Radiation Protection
A sample of radioactive material is reported to contain 2000 picocuries
of activity. Express this value as disintegrations per minute.
A) 370 dpm
B) 900 dpm
C) 3770 dpm
,3|Page
D) 4440 dpm
E) 5320 dpm ......ANSWER......The correct answer is: D
dps = (2000 pCi)(1 x 10-12Ci/pi )(3.7x1010 dps/Ci) dps = 74
dpm = (74 dps) (60 sec/min)
dpm = 4440
Remember to convert to disintegrations per minute not
DISINTEGRATIONS PER SECOND.
Question Number: 1
Fundamentals of Radiation Protection
A low energy alpha detector is usually effective if the detector is distant
from the source.
A) 1/4 inch
B) 1/2 inch
C) 1 inch
D) 1 1/2 inches
E) 2 inches ......ANSWER......The correct answer is: A
Low energy alpha particles can only travel less than 1/2 inch in air.
Therefore, one must be closer than this to detect them.
, 4|Page
Question Number: 2
Fundamentals of Radiation Protection
A sample of I-131 (half life = 8 days) is kept for 80 days, at which time
the activity is 1 µCi . What was the original activity?
A) 2.0 mCi
B) 1.0 mCi
C) 1.5 mCi
D) 3.5 mCi
E) 4.0 mCi ......ANSWER......The correct answer is: B
After 10 half lives, the remaining activity is approximately 1000th of the
original amount. Therefore, if there was 1
µCi left after 10 half lives, then there must have been 1000 times more
to start with. Hence, 1 µCi * 1000 = 1 mCi.
Question Number: 3
Fundamentals of Radiation Protection
A sample of radioactive material is reported to contain 2000 picocuries
of activity. Express this value as
