NRRPT Prep Exam 2025/2026 | 160+ Practice Questions with
Detailed Rationales, Real Exam Simulation, and A+
Guaranteed Pass Study Guide for Nursing Readiness &
Clinical Success
Questions 1–165
1. Which type of radiation consists of two protons and two neutrons?
A) Beta minus
B) Gamma
C) Alpha
D) Neutron
Correct Answer: C
Rationale: Alpha particles are helium-4 nuclei (2 protons, 2 neutrons). Beta minus
is an electron, gamma is electromagnetic, neutron is uncharged.
2. The half-life of Cs-137 is approximately:
A) 2 years
B) 8 days
C) 30 years
D) 5.27 years
Correct Answer: C
Rationale: Cs-137 half-life is 30.17 years. I-131 is 8 days, Co-60 is 5.27 years.
3. What is the approximate annual effective dose limit for a radiation worker
(occupational) in the US?
A) 1 mSv
B) 5 mSv
C) 50 mSv
D) 500 mSv
, Correct Answer: C
Rationale: NRC occupational limit is 50 mSv (5 rem) per year total effective dose
equivalent.
4. Which detector is best for fast neutron dosimetry?
A) Geiger-Müller tube
B) Scintillation (NaI)
C) CR-39 (solid state track detector)
D) Ionization chamber
Correct Answer: C
Rationale: CR-39 detects recoil protons from fast neutron interactions. GM and
NaI are gamma sensitive.
5. The inverse square law states that exposure rate is proportional to:
A) 1/r
B) 1/r²
C) r²
D) r
Correct Answer: B
Rationale: For a point source, intensity ∝ 1/r². Doubling distance reduces
exposure to 1/4.
6. What is the primary photoelectric effect dependence on atomic number (Z)?
A) ~Z
B) ~Z²
C) ~Z³
D) ~Z⁴
Correct Answer: D
Rationale: Photoelectric probability ∝ Z⁴ / E³. Important for high-Z materials like
lead.
Detailed Rationales, Real Exam Simulation, and A+
Guaranteed Pass Study Guide for Nursing Readiness &
Clinical Success
Questions 1–165
1. Which type of radiation consists of two protons and two neutrons?
A) Beta minus
B) Gamma
C) Alpha
D) Neutron
Correct Answer: C
Rationale: Alpha particles are helium-4 nuclei (2 protons, 2 neutrons). Beta minus
is an electron, gamma is electromagnetic, neutron is uncharged.
2. The half-life of Cs-137 is approximately:
A) 2 years
B) 8 days
C) 30 years
D) 5.27 years
Correct Answer: C
Rationale: Cs-137 half-life is 30.17 years. I-131 is 8 days, Co-60 is 5.27 years.
3. What is the approximate annual effective dose limit for a radiation worker
(occupational) in the US?
A) 1 mSv
B) 5 mSv
C) 50 mSv
D) 500 mSv
, Correct Answer: C
Rationale: NRC occupational limit is 50 mSv (5 rem) per year total effective dose
equivalent.
4. Which detector is best for fast neutron dosimetry?
A) Geiger-Müller tube
B) Scintillation (NaI)
C) CR-39 (solid state track detector)
D) Ionization chamber
Correct Answer: C
Rationale: CR-39 detects recoil protons from fast neutron interactions. GM and
NaI are gamma sensitive.
5. The inverse square law states that exposure rate is proportional to:
A) 1/r
B) 1/r²
C) r²
D) r
Correct Answer: B
Rationale: For a point source, intensity ∝ 1/r². Doubling distance reduces
exposure to 1/4.
6. What is the primary photoelectric effect dependence on atomic number (Z)?
A) ~Z
B) ~Z²
C) ~Z³
D) ~Z⁴
Correct Answer: D
Rationale: Photoelectric probability ∝ Z⁴ / E³. Important for high-Z materials like
lead.
