NRRPT EXAM AND PRACTICE EXAM NEWEST 2026
TEST BANK| NATIONAL REGISTRY OF RADIATION
PROTECTION TECHNICIAN CERTIFICATION EXAM PREP
WITH COMPLETE 1000+ REAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+ (BRAND NEW!!)
1. A worker accidentally ingests one mCi of tritium (H-3). How
many disintegrations per second (dps) occur in the worker's
body?
A. 3.7 x 10⁷ dps
B. 2.5 x 10³ dps
C. 1.7 x 10⁸ dps
D. 2.2 x 10⁶ dps
E. 3.7 x 10¹⁰ dps
Correct Answer: A. 3.7 x 10⁷ dps
Rationale: By definition, 1 mCi = 3.7 x 10⁷ disintegrations per
second. This is a fundamental conversion that all radiation
1
,protection technologists must memorize. One curie equals 3.7 x
10¹⁰ dps, so one millicurie equals 3.7 x 10⁷ dps .
2. A low-energy alpha detector is most effective at what
maximum distance from the source?
A. 1/4 inch
B. 1/2 inch
C. 1 inch
D. 1 1/2 inches
E. 2 inches
Correct Answer: A. 1/4 inch
Rationale: Low-energy alpha particles can travel less than 1/2
inch in air. For effective detection, the detector must be closer
than this distance. At 1/4 inch, detection is reliable; at greater
distances, alpha particles lose energy before reaching the
detector .
3. What is the half-life of H-3 (Tritium)?
A. 5.27 years
B. 8.04 days
2
,C. 12.3 years
D. 29.1 years
E. 30.07 years
Correct Answer: C. 12.3 years
Rationale: Tritium (H-3) has a half-life of 12.3 years and decays
by beta-minus emission. This is one of the fundamental
radionuclide half-lives that NRRPT candidates must memorize .
4. How does Carbon-14 decay?
A. Alpha emission
B. Beta-minus emission
C. Beta-plus emission
D. Electron capture
E. Gamma emission
Correct Answer: B. Beta-minus emission
Rationale: Carbon-14 decays by beta-minus emission (β⁻). This
cosmogenic radionuclide is used extensively in radiocarbon
dating. The neutron-to-proton ratio is too high, so a neutron
converts to a proton, emitting an electron and an antineutrino .
3
, 5. What is the half-life of Co-60?
A. 5.27 years
B. 8.04 days
C. 12.3 years
D. 29.1 years
E. 30.07 years
Correct Answer: A. 5.27 years
Rationale: Cobalt-60 has a half-life of 5.27 years and decays
by beta-minus emission to Nickel-60, followed by emission of two
gamma photons (1.17 and 1.33 MeV). It is a common industrial
radiography source and teletherapy source .
6. 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
4
TEST BANK| NATIONAL REGISTRY OF RADIATION
PROTECTION TECHNICIAN CERTIFICATION EXAM PREP
WITH COMPLETE 1000+ REAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED ANSWERS)
ALREADY GRADED A+ (BRAND NEW!!)
1. A worker accidentally ingests one mCi of tritium (H-3). How
many disintegrations per second (dps) occur in the worker's
body?
A. 3.7 x 10⁷ dps
B. 2.5 x 10³ dps
C. 1.7 x 10⁸ dps
D. 2.2 x 10⁶ dps
E. 3.7 x 10¹⁰ dps
Correct Answer: A. 3.7 x 10⁷ dps
Rationale: By definition, 1 mCi = 3.7 x 10⁷ disintegrations per
second. This is a fundamental conversion that all radiation
1
,protection technologists must memorize. One curie equals 3.7 x
10¹⁰ dps, so one millicurie equals 3.7 x 10⁷ dps .
2. A low-energy alpha detector is most effective at what
maximum distance from the source?
A. 1/4 inch
B. 1/2 inch
C. 1 inch
D. 1 1/2 inches
E. 2 inches
Correct Answer: A. 1/4 inch
Rationale: Low-energy alpha particles can travel less than 1/2
inch in air. For effective detection, the detector must be closer
than this distance. At 1/4 inch, detection is reliable; at greater
distances, alpha particles lose energy before reaching the
detector .
3. What is the half-life of H-3 (Tritium)?
A. 5.27 years
B. 8.04 days
2
,C. 12.3 years
D. 29.1 years
E. 30.07 years
Correct Answer: C. 12.3 years
Rationale: Tritium (H-3) has a half-life of 12.3 years and decays
by beta-minus emission. This is one of the fundamental
radionuclide half-lives that NRRPT candidates must memorize .
4. How does Carbon-14 decay?
A. Alpha emission
B. Beta-minus emission
C. Beta-plus emission
D. Electron capture
E. Gamma emission
Correct Answer: B. Beta-minus emission
Rationale: Carbon-14 decays by beta-minus emission (β⁻). This
cosmogenic radionuclide is used extensively in radiocarbon
dating. The neutron-to-proton ratio is too high, so a neutron
converts to a proton, emitting an electron and an antineutrino .
3
, 5. What is the half-life of Co-60?
A. 5.27 years
B. 8.04 days
C. 12.3 years
D. 29.1 years
E. 30.07 years
Correct Answer: A. 5.27 years
Rationale: Cobalt-60 has a half-life of 5.27 years and decays
by beta-minus emission to Nickel-60, followed by emission of two
gamma photons (1.17 and 1.33 MeV). It is a common industrial
radiography source and teletherapy source .
6. 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
4
