NMTCB Radiation Safety Exam 2026/2027 | 300+ Practice
Questions, Correct Answers & Detailed Rationales
RAM LICENSE, RADIATION PHYSICS, INSTRUMENTATION & DOSIMETRY
1. What does ALARA mean in radiation protection?
A. As Low As Reasonably Achievable
B. As Low As Radiation Allows
C. Applied Limits Against Radiation Areas
D. Authorized Levels of Annual Radiation Assessment
Answer: A
Rationale: ALARA is the fundamental optimization principle requiring
radiation exposures to be kept as low as reasonably achievable while
accomplishing the necessary task.
2. Which quantity measures radioactive decay rate?
A. Gray
B. Becquerel
C. Sievert
D. Tesla
Answer: B
Rationale: The becquerel (Bq) is the SI unit of activity and represents
one nuclear transformation per second.
3. Which SI unit measures absorbed dose?
A. Gy
B. Sv
C. Bq
D. C/kg
,Answer: A
Rationale: Gray is the SI unit of absorbed dose and represents joules of
radiation energy deposited per kilogram of material.
4. Which SI unit measures equivalent dose?
A. Bq
B. Gy
C. Sv
D. Ci
Answer: C
Rationale: Sievert incorporates radiation weighting and is used for
equivalent and effective dose.
5. Which SI unit measures activity?
A. Becquerel
B. Gray
C. Sievert
D. Roentgen
Answer: A
Rationale: One becquerel equals one nuclear transformation per
second.
6. What is the approximate relationship between 1 Ci and Bq?
A. 3.7 × 10¹⁰ Bq
B. 3.7 × 10⁶ Bq
C. 3.7 × 10⁸ Bq
D. 3.7 × 10¹² Bq
,Answer: A
Rationale: One curie is approximately 3.7 × 10¹⁰ transformations per
second.
7. What happens to radiation intensity when distance from a point
source is doubled?
A. It doubles
B. It is halved
C. It becomes one-fourth
D. It becomes four times greater
Answer: C
Rationale: Intensity follows the inverse-square law, so doubling distance
reduces intensity to 1/4.
8. If distance from a point source is tripled, intensity becomes
approximately:
A. 1/3
B. 1/6
C. 1/9
D. 1/12
Answer: C
Rationale: The inverse-square law gives 1/3² = 1/9.
9. Which radiation has the greatest linear energy transfer among these
choices?
A. Gamma rays
B. X-rays
C. Alpha particles
D. Visible light
, Answer: C
Rationale: Alpha particles deposit energy densely over a short path and
have high LET.
10. Which radiation is electromagnetic?
A. Alpha particle
B. Beta particle
C. Gamma ray
D. Neutron
Answer: C
Rationale: Gamma rays are high-energy electromagnetic photons.
11. Which decay produces a positron?
A. Beta-minus
B. Beta-plus
C. Alpha
D. Electron capture only
Answer: B
Rationale: Beta-plus decay converts a proton to a neutron while
emitting a positron.
12. What particle is emitted during beta-minus decay?
A. Positron
B. Electron
C. Proton
D. Alpha particle
Answer: B
Rationale: Beta-minus decay emits an electron from the nucleus.
Questions, Correct Answers & Detailed Rationales
RAM LICENSE, RADIATION PHYSICS, INSTRUMENTATION & DOSIMETRY
1. What does ALARA mean in radiation protection?
A. As Low As Reasonably Achievable
B. As Low As Radiation Allows
C. Applied Limits Against Radiation Areas
D. Authorized Levels of Annual Radiation Assessment
Answer: A
Rationale: ALARA is the fundamental optimization principle requiring
radiation exposures to be kept as low as reasonably achievable while
accomplishing the necessary task.
2. Which quantity measures radioactive decay rate?
A. Gray
B. Becquerel
C. Sievert
D. Tesla
Answer: B
Rationale: The becquerel (Bq) is the SI unit of activity and represents
one nuclear transformation per second.
3. Which SI unit measures absorbed dose?
A. Gy
B. Sv
C. Bq
D. C/kg
,Answer: A
Rationale: Gray is the SI unit of absorbed dose and represents joules of
radiation energy deposited per kilogram of material.
4. Which SI unit measures equivalent dose?
A. Bq
B. Gy
C. Sv
D. Ci
Answer: C
Rationale: Sievert incorporates radiation weighting and is used for
equivalent and effective dose.
5. Which SI unit measures activity?
A. Becquerel
B. Gray
C. Sievert
D. Roentgen
Answer: A
Rationale: One becquerel equals one nuclear transformation per
second.
6. What is the approximate relationship between 1 Ci and Bq?
A. 3.7 × 10¹⁰ Bq
B. 3.7 × 10⁶ Bq
C. 3.7 × 10⁸ Bq
D. 3.7 × 10¹² Bq
,Answer: A
Rationale: One curie is approximately 3.7 × 10¹⁰ transformations per
second.
7. What happens to radiation intensity when distance from a point
source is doubled?
A. It doubles
B. It is halved
C. It becomes one-fourth
D. It becomes four times greater
Answer: C
Rationale: Intensity follows the inverse-square law, so doubling distance
reduces intensity to 1/4.
8. If distance from a point source is tripled, intensity becomes
approximately:
A. 1/3
B. 1/6
C. 1/9
D. 1/12
Answer: C
Rationale: The inverse-square law gives 1/3² = 1/9.
9. Which radiation has the greatest linear energy transfer among these
choices?
A. Gamma rays
B. X-rays
C. Alpha particles
D. Visible light
, Answer: C
Rationale: Alpha particles deposit energy densely over a short path and
have high LET.
10. Which radiation is electromagnetic?
A. Alpha particle
B. Beta particle
C. Gamma ray
D. Neutron
Answer: C
Rationale: Gamma rays are high-energy electromagnetic photons.
11. Which decay produces a positron?
A. Beta-minus
B. Beta-plus
C. Alpha
D. Electron capture only
Answer: B
Rationale: Beta-plus decay converts a proton to a neutron while
emitting a positron.
12. What particle is emitted during beta-minus decay?
A. Positron
B. Electron
C. Proton
D. Alpha particle
Answer: B
Rationale: Beta-minus decay emits an electron from the nucleus.
