FLORIDA BOARD OF PROFESSIONAL
ENGINEERS PRINCIPLES AND PRACTICE
NUCLEAR EXAM WITH ACTUAL QUESTIONS
AND VERIFIED ANSWERS, PLUS
EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Radioactive Decay
A radioactive isotope has a half-life of 8 hours. If a sealed sample
initially contains 1.60×1012 atoms of the isotope, approximately how
many atoms remain after 24 hours?
A. 8.00×1011
B. 4.00×1011
C. 2.00×1011
D. 1.00×1011
Answer: C. 2.00×1011
Rationale: The elapsed time is 24 hours, corresponding to three half-
lives because 24/8=3. The remaining fraction is (1/2)3=1/8. Therefore,
1.60×1012/8=2.00×1011 atoms.
2. Decay Constant and Activity
A radionuclide has a half-life of 30 days. Which expression correctly
represents its decay constant?
A. λ=30 day−1
B. λ=1/30 day−1
1
,C. λ=ln(2)/30 day−1
D. λ=30/ln(2) day−1
Answer: C. λ=ln(2)/30 day−1
Rationale: The relationship between half-life and decay constant is
T1/2=ln(2)/λ. Rearranging gives λ=ln(2)/T1/2. The decay constant
therefore equals approximately 0.0231 day−1.
3. Radioactive Decay Chain
A parent radionuclide decays into a radioactive daughter. The parent has
a half-life of 100 years, while the daughter has a half-life of 2 hours.
After sufficient time has elapsed following purification of the parent, the
daughter activity will tend toward:
A. Zero permanently
B. The parent activity
C. Twice the parent activity
D. Half the parent activity
Answer: B. The parent activity
Rationale: When the daughter half-life is much shorter than the
parent half-life, the daughter approaches secular equilibrium with the
parent. Once equilibrium is established, the daughter is produced at
approximately the same rate at which it decays, so its activity
approaches the parent activity.
4. Nuclear Binding Energy
The primary reason energy is released during nuclear fission of a heavy
nucleus is that:
2
,A. Electrons are converted directly into photons
B. The fission products have a greater total mass than the original
nucleus
C. The fission products have greater binding energy per nucleon than the
original heavy nucleus
D. Neutrons lose their rest mass during the reaction
Answer: C. The fission products have greater binding energy per
nucleon than the original heavy nucleus
Rationale: Heavy nuclei such as uranium-235 have lower binding
energy per nucleon than medium-mass fission products. Moving
toward a more tightly bound configuration reduces the total nuclear
mass. The corresponding mass defect is converted to energy according
to E=mc2.
5. Fission Energy
Approximately 200 MeV of energy is released per thermal-neutron-
induced fission of a typical fissile heavy nucleus. If 1020 fissions occur,
what is the approximate energy released?
A. 3.2×103 J
B. 3.2×106 J
C. 3.2×109 J
D. 3.2×1012 J
Answer: C. 3.2×109 J
Rationale: One fission releases approximately 200 MeV. Since
1 eV=1.602×10−19 J, 200 MeV corresponds to approximately
3.204×10−11 J. Multiplying by 1020 fissions gives approximately
3.2×109 J.
3
, 6. Compton Scattering
A photon interacts with an electron primarily through Compton
scattering. Which statement is correct?
A. The photon disappears and transfers all energy to the electron
B. The photon is scattered with reduced energy and the electron receives
recoil energy
C. The photon produces an electron-positron pair without a nucleus
D. The photon can only interact if its energy exceeds 1.022 MeV
Answer: B. The photon is scattered with reduced energy and the
electron receives recoil energy
Rationale: In Compton scattering, an incident photon transfers part of
its energy and momentum to an electron. The photon continues in a
different direction with lower energy. Pair production requires a
photon energy above 1.022 MeV and normally occurs in the field of a
nucleus.
7. Pair Production
A gamma photon with energy 2.0 MeV undergoes pair production.
Ignoring recoil, the maximum kinetic energy available to the electron-
positron pair is:
A. 0.511 MeV
B. 1.022 MeV
C. 0.978 MeV
D. 2.0 MeV
Answer: C. 0.978 MeV
Rationale: Pair production requires 1.022 MeV to create the electron
and positron rest masses. The remaining energy becomes kinetic
energy: 2.000−1.022=0.978 MeV.
4
ENGINEERS PRINCIPLES AND PRACTICE
NUCLEAR EXAM WITH ACTUAL QUESTIONS
AND VERIFIED ANSWERS, PLUS
EXPLAINED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED 100% PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1. Radioactive Decay
A radioactive isotope has a half-life of 8 hours. If a sealed sample
initially contains 1.60×1012 atoms of the isotope, approximately how
many atoms remain after 24 hours?
A. 8.00×1011
B. 4.00×1011
C. 2.00×1011
D. 1.00×1011
Answer: C. 2.00×1011
Rationale: The elapsed time is 24 hours, corresponding to three half-
lives because 24/8=3. The remaining fraction is (1/2)3=1/8. Therefore,
1.60×1012/8=2.00×1011 atoms.
2. Decay Constant and Activity
A radionuclide has a half-life of 30 days. Which expression correctly
represents its decay constant?
A. λ=30 day−1
B. λ=1/30 day−1
1
,C. λ=ln(2)/30 day−1
D. λ=30/ln(2) day−1
Answer: C. λ=ln(2)/30 day−1
Rationale: The relationship between half-life and decay constant is
T1/2=ln(2)/λ. Rearranging gives λ=ln(2)/T1/2. The decay constant
therefore equals approximately 0.0231 day−1.
3. Radioactive Decay Chain
A parent radionuclide decays into a radioactive daughter. The parent has
a half-life of 100 years, while the daughter has a half-life of 2 hours.
After sufficient time has elapsed following purification of the parent, the
daughter activity will tend toward:
A. Zero permanently
B. The parent activity
C. Twice the parent activity
D. Half the parent activity
Answer: B. The parent activity
Rationale: When the daughter half-life is much shorter than the
parent half-life, the daughter approaches secular equilibrium with the
parent. Once equilibrium is established, the daughter is produced at
approximately the same rate at which it decays, so its activity
approaches the parent activity.
4. Nuclear Binding Energy
The primary reason energy is released during nuclear fission of a heavy
nucleus is that:
2
,A. Electrons are converted directly into photons
B. The fission products have a greater total mass than the original
nucleus
C. The fission products have greater binding energy per nucleon than the
original heavy nucleus
D. Neutrons lose their rest mass during the reaction
Answer: C. The fission products have greater binding energy per
nucleon than the original heavy nucleus
Rationale: Heavy nuclei such as uranium-235 have lower binding
energy per nucleon than medium-mass fission products. Moving
toward a more tightly bound configuration reduces the total nuclear
mass. The corresponding mass defect is converted to energy according
to E=mc2.
5. Fission Energy
Approximately 200 MeV of energy is released per thermal-neutron-
induced fission of a typical fissile heavy nucleus. If 1020 fissions occur,
what is the approximate energy released?
A. 3.2×103 J
B. 3.2×106 J
C. 3.2×109 J
D. 3.2×1012 J
Answer: C. 3.2×109 J
Rationale: One fission releases approximately 200 MeV. Since
1 eV=1.602×10−19 J, 200 MeV corresponds to approximately
3.204×10−11 J. Multiplying by 1020 fissions gives approximately
3.2×109 J.
3
, 6. Compton Scattering
A photon interacts with an electron primarily through Compton
scattering. Which statement is correct?
A. The photon disappears and transfers all energy to the electron
B. The photon is scattered with reduced energy and the electron receives
recoil energy
C. The photon produces an electron-positron pair without a nucleus
D. The photon can only interact if its energy exceeds 1.022 MeV
Answer: B. The photon is scattered with reduced energy and the
electron receives recoil energy
Rationale: In Compton scattering, an incident photon transfers part of
its energy and momentum to an electron. The photon continues in a
different direction with lower energy. Pair production requires a
photon energy above 1.022 MeV and normally occurs in the field of a
nucleus.
7. Pair Production
A gamma photon with energy 2.0 MeV undergoes pair production.
Ignoring recoil, the maximum kinetic energy available to the electron-
positron pair is:
A. 0.511 MeV
B. 1.022 MeV
C. 0.978 MeV
D. 2.0 MeV
Answer: C. 0.978 MeV
Rationale: Pair production requires 1.022 MeV to create the electron
and positron rest masses. The remaining energy becomes kinetic
energy: 2.000−1.022=0.978 MeV.
4
