2026 NEWEST NRRPT EXAM PREP
QUESTIONS FREQUENTLY TESTED WITH
QUESTIONS AND CORRECT ANSWERS
GRADED A+
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 Correct 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
,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 Correct 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
D) 4440 dpm
E) 5320 dpm Correct 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 Correct 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
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 Correct 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
QUESTIONS FREQUENTLY TESTED WITH
QUESTIONS AND CORRECT ANSWERS
GRADED A+
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 Correct 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
,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 Correct 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
D) 4440 dpm
E) 5320 dpm Correct 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 Correct 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
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 Correct 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
