200 Nuclear Physics MCQs for JEE, NEET, SAT, Olympiad | With Explanations

Nuclear Physics 

This module provides 200 Nuclear Physics MCQs with answers and explanations, covering key topics such as radioactive decay, nuclear fission, nuclear fusion, nuclear models, detectors, and applications. Each question is designed to strengthen conceptual clarity and prepare students for competitive exams like JEE, NEET, SAT, and Olympiad.

Readers will gain a complete Nuclear Physics question bank that balances fundamental concepts, advanced applications, and exam-oriented practice. With detailed solutions, this resource ensures mastery of binding energy, half-life, nuclear reactions, radiation units, and safety protocols, making it a reliable tool for revision, exam prep, and real-world applications.

Q1. The nucleus of an atom consists of:

(a) Protons and neutrons ✅

(b) Protons and electrons

(c) Neutrons and electrons

(d) Only protons

Explanation: The nucleus is made of nucleons (protons and neutrons). Electrons orbit outside the nucleus.

Q2. The nuclear force is:

(a) Strong, short-range, charge-independent ✅

(b) Weak, long-range

(c) Electrostatic

(d) Random

Explanation: Nuclear force binds nucleons together, stronger than Coulomb force but effective only at ~1–2 fm.

Q3. Mass defect is:

(a) Difference between sum of nucleon masses and actual nuclear mass ✅

(b) Difference between proton and neutron mass

(c) Random

(d) None

Explanation: Mass defect arises due to binding energy; missing mass converts into nuclear binding energy.

Q4. Binding energy per nucleon is maximum for:

(a) Iron (Fe) ✅

(b) Uranium

(c) Hydrogen

(d) Helium

Explanation: Iron-56 has highest stability; explains why fusion of light nuclei and fission of heavy nuclei release energy.

Q5. Radioactive decay is:

(a) Spontaneous disintegration of unstable nucleus ✅

(b) Fusion of nuclei

(c) Random

(d) None

Explanation: Unstable nuclei emit radiation (α, β, γ) to achieve stability.

Q6. Alpha decay emits:

(a) Helium nucleus (2p + 2n) ✅

(b) Electron

(c) Photon

(d) Proton

Explanation: Alpha particle reduces mass number by 4 and atomic number by 2.

Q7. Beta-minus decay emits:

(a) Electron and antineutrino ✅

(b) Proton

(c) Photon

(d) Positron

Explanation: Neutron converts into proton, emitting electron and antineutrino.

Q8. Beta-plus decay emits:

(a) Positron and neutrino ✅

(b) Electron

(c) Proton

(d) Neutron

Explanation: Proton converts into neutron, emitting positron and neutrino.

Q9. Gamma decay emits:

(a) Photon ✅

(b) Electron

(c) Proton

(d) Neutron

Explanation: Excited nucleus releases excess energy as gamma radiation without changing nucleon number.

Q10. Half-life is:

(a) Time for half of radioactive nuclei to decay ✅

(b) Time for all nuclei to decay

(c) Random

(d) None

Explanation: Characteristic property of isotope, independent of initial amount.

Q11. Activity of radioactive sample is:

(a) Rate of decay (A = λN) ✅

(b) Total number of atoms

(c) Random

(d) None

Explanation: Activity measured in Becquerel (1 decay per second).

Q12. Decay constant (λ) relates to half-life as:

(a) λ = ln2 / T½ ✅

(b) λ = T½ / ln2

(c) Random

(d) None

Explanation: Higher decay constant means shorter half-life.

Q13. Isotopes are:

(a) Same Z, different A ✅

(b) Same A, different Z

(c) Random

(d) None

Explanation: Isotopes have same atomic number but different mass numbers.

Q14. Isobars are:

(a) Same A, different Z ✅

(b) Same Z, different A

(c) Random

(d) None

Explanation: Example: 40Ar and 40Ca.

Q15. Isotones are:

(a) Same number of neutrons ✅

(b) Same number of protons

(c) Random

(d) None

Explanation: Example: 14C and 15N both have 8 neutrons.

Q16. Nuclear fission is:

(a) Splitting of heavy nucleus into lighter nuclei ✅

(b) Combining of light nuclei

(c) Random

(d) None

Explanation: Releases large energy, basis of nuclear reactors.

Q17. Nuclear fusion is:

(a) Combining of light nuclei into heavier nucleus ✅

(b) Splitting of heavy nucleus

(c) Random

(d) None

Explanation: Powers stars and hydrogen bombs, requires high temperature.

Q18. Q-value of nuclear reaction is:

(a) Difference in mass-energy of reactants and products ✅

(b) Sum of masses

(c) Random

(d) None

Explanation: Positive Q means exothermic reaction, negative Q means endothermic.

Q19. Chain reaction in fission is sustained by:

(a) Neutrons ✅

(b) Protons

(c) Electrons

(d) Photons

Explanation: Released neutrons induce further fission, sustaining reaction.

Q20. Moderator in nuclear reactor is:

(a) Slows down neutrons ✅

(b) Absorbs neutrons

(c) Random

(d) None

Explanation: Materials like graphite or heavy water slow neutrons for effective fission.

Q21. Control rods in reactor are:

(a) Absorb excess neutrons ✅

(b) Increase neutron speed

(c) Random

(d) None

Explanation: Made of cadmium or boron, regulate chain reaction.

Q22. Binding energy curve explains:

(a) Fusion of light nuclei and fission of heavy nuclei release energy ✅

(b) Only fusion releases energy

(c) Random

(d) None

Explanation: Curve peaks at iron, showing maximum stability.

Q23. Nuclear force is saturated because:

(a) Each nucleon interacts only with nearest neighbors ✅

(b) Each nucleon interacts with all

(c) Random

(d) None

Explanation: Explains constant density of nuclei.

Q24. Nuclear radius formula is:

(a) R = R₀A^(1/3) ✅

(b) R = R₀A^(1/2)

(c) Random

(d) None

Explanation: Radius proportional to cube root of mass number, R₀ ≈ 1.2 fm.

Q25. Nuclear density is:

(a) Nearly constant for all nuclei ✅

(b) Varies with mass number

(c) Random

(d) None

Explanation: Because volume ∝ A and mass ∝ A, density remains constant (~2.3 × 10¹⁷ kg/m³).

Q26. Nuclear reaction conserves:

(a) Energy, momentum, charge, nucleon number ✅

(b) Only energy

(c) Only charge

(d) None

Explanation: All fundamental conservation laws hold in nuclear reactions, including lepton number in particle processes.

Q27. Q-value of nuclear reaction is:

(a) Difference in mass-energy of reactants and products ✅

(b) Sum of masses

(c) Random

(d) None

Explanation: Positive Q means exothermic reaction; negative Q means endothermic requiring energy input.

Q28. Threshold energy is required for:

(a) Endothermic nuclear reactions ✅

(b) Exothermic reactions

(c) Random

(d) None

Explanation: Minimum kinetic energy needed to initiate a reaction with negative Q-value.

Q29. Nuclear fission releases energy because:

(a) Binding energy per nucleon increases ✅

(b) Binding energy decreases

(c) Random

(d) None

Explanation: Heavy nuclei split into medium nuclei with higher binding energy per nucleon, releasing energy.

Q30. Nuclear fusion requires:

(a) High temperature and pressure ✅

(b) Low temperature

(c) Random

(d) None

Explanation: Coulomb barrier between nuclei is overcome only at very high thermal energies.

Q31. Chain reaction in fission is sustained by:

(a) Neutrons ✅

(b) Protons

(c) Electrons

(d) Photons

Explanation: Released neutrons induce further fission, sustaining the reaction.

Q32. Critical mass is:

(a) Minimum mass of fissile material for chain reaction ✅

(b) Maximum mass

(c) Random

(d) None

Explanation: Below critical mass, neutrons escape without sustaining reaction.

Q33. Moderator in nuclear reactor:

(a) Slows down neutrons ✅

(b) Absorbs neutrons

(c) Random

(d) None

Explanation: Graphite or heavy water slows neutrons to thermal energies for effective fission.

Q34. Control rods are made of:

(a) Cadmium or boron ✅

(b) Iron

(c) Random

(d) None

Explanation: These materials absorb excess neutrons, regulating chain reaction.

Q35. Fast breeder reactor uses:

(a) Fast neutrons to produce more fissile material ✅

(b) Slow neutrons

(c) Random

(d) None

Explanation: Converts fertile isotopes like U-238 into fissile Pu-239.

Q36. Fusion in stars occurs due to:

(a) High temperature and pressure in core ✅

(b) Low temperature

(c) Random

(d) None

Explanation: Hydrogen nuclei fuse into helium, releasing enormous energy.

Q37. Proton-proton chain is:

(a) Fusion process in stars like Sun ✅

(b) Fission process

(c) Random

(d) None

Explanation: Converts hydrogen into helium through multiple steps.

Q38. CNO cycle is:

(a) Fusion process in massive stars ✅

(b) Fission process

(c) Random

(d) None

Explanation: Carbon, nitrogen, oxygen act as catalysts in hydrogen fusion.

Q39. Binding energy curve explains:

(a) Fusion of light nuclei and fission of heavy nuclei release energy ✅

(b) Only fusion releases energy

(c) Random

(d) None

Explanation: Curve peaks at iron, showing maximum stability.

Q40. Nuclear density is:

(a) Nearly constant for all nuclei ✅

(b) Varies with mass number

(c) Random

(d) None

Explanation: Because volume ∝ A and mass ∝ A, density remains constant (~2.3 × 10¹⁷ kg/m³).

Q41. Nuclear radius formula is:

(a) R = R₀A^(1/3) ✅

(b) R = R₀A^(1/2)

(c) Random

(d) None

Explanation: Radius proportional to cube root of mass number, R₀ ≈ 1.2 fm.

Q42. Liquid drop model explains:

(a) Nuclear fission ✅

(b) Nuclear fusion

(c) Random

(d) None

Explanation: Treats nucleus like charged liquid drop, explains deformation and splitting.

Q43. Shell model explains:

(a) Magic numbers of stability ✅

(b) Fission

(c) Random

(d) None

Explanation: Certain nucleon numbers (2, 8, 20, 28, 50, 82, 126) give extra stability.

Q44. Magic numbers are:

(a) Nucleon numbers giving extra stability ✅

(b) Atomic numbers

(c) Random

(d) None

Explanation: Explained by shell model, nuclei with magic numbers are more stable.

Q45. Nuclear spin arises from:

(a) Intrinsic spin of nucleons ✅

(b) Orbital motion of electrons

(c) Random

(d) None

Explanation: Nucleons have intrinsic spin, contributing to nuclear angular momentum.

Q46. Nuclear magnetic moment arises from:

(a) Spin and orbital motion of nucleons ✅

(b) Electron spin

(c) Random

(d) None

Explanation: Combination of spin and orbital contributions of protons and neutrons.

Q47. Radioactive tracers are used in:

(a) Medical imaging and industry ✅

(b) Cooking

(c) Random

(d) None

Explanation: Isotopes like Tc-99m used in diagnostic imaging.

Q48. Radiation therapy uses:

(a) Gamma rays and beta particles ✅

(b) Alpha particles only

(c) Random

(d) None

Explanation: High-energy radiation destroys cancer cells.

Q49. Radiation units include:

(a) Becquerel, Gray, Sievert ✅

(b) Joule, Watt

(c) Random

(d) None

Explanation: Becquerel measures activity, Gray measures absorbed dose, Sievert measures biological effect.

Q50. Biological effect of radiation depends on:

(a) Type, energy, dose, exposure time ✅

(b) Only dose

(c) Random

(d) None

Explanation: Different radiations have different penetration and damage potential; measured in Sieverts.

Q51. Nuclear reaction cross-section measures:

(a) Probability of reaction ✅

(b) Energy released

(c) Random

(d) None

Explanation: Cross-section (σ) represents effective area for interaction, measured in barns (1 barn = 10⁻²⁸ m²).

Q52. Neutron activation analysis is used for:

(a) Detecting trace elements ✅

(b) Measuring mass

(c) Random

(d) None

Explanation: Sample irradiated with neutrons becomes radioactive; emitted radiation identifies elements.

Q53. Nuclear reactor fuel commonly used is:

(a) Uranium-235 ✅

(b) Carbon

(c) Random

(d) None

Explanation: U-235 undergoes fission with thermal neutrons, releasing energy.

Q54. Fertile material in reactors is:

(a) Uranium-238 ✅

(b) Uranium-235

(c) Random

(d) None

Explanation: U-238 absorbs neutrons to form fissile Pu-239.

Q55. Fissile material is:

(a) Capable of sustaining chain reaction ✅

(b) Only fertile

(c) Random

(d) None

Explanation: Examples: U-235, Pu-239, U-233.

Q56. Breeder reactor produces:

(a) More fissile material than consumed ✅

(b) Less fissile material

(c) Random

(d) None

Explanation: Converts fertile isotopes into fissile ones, increasing fuel supply.

Q57. Fusion reaction in Sun is:

(a) Proton-proton chain ✅

(b) Fission

(c) Random

(d) None

Explanation: Hydrogen nuclei fuse into helium, releasing energy.

Q58. CNO cycle occurs in:

(a) Massive stars ✅

(b) Small stars

(c) Random

(d) None

Explanation: Carbon, nitrogen, oxygen act as catalysts in hydrogen fusion.

Q59. Tokamak is:

(a) Device for controlled nuclear fusion ✅

(b) Fission reactor

(c) Random

(d) None

Explanation: Magnetic confinement device for plasma in fusion research.

Q60. Binding energy curve shows:

(a) Stability maximum at iron ✅

(b) Stability maximum at uranium

(c) Random

(d) None

Explanation: Explains why fusion of light nuclei and fission of heavy nuclei release energy.

Q61. Nuclear force properties include:

(a) Strong, short-range, saturating ✅

(b) Weak, long-range

(c) Random

(d) None

Explanation: Acts only between nearest nucleons, independent of charge.

Q62. Saturation of nuclear force means:

(a) Each nucleon interacts with limited neighbors ✅

(b) Each nucleon interacts with all

(c) Random

(d) None

Explanation: Explains constant nuclear density.

Q63. Nuclear density is:

(a) Nearly constant for all nuclei ✅

(b) Varies with mass number

(c) Random

(d) None

Explanation: Because mass ∝ A and volume ∝ A, density remains constant.

Q64. Nuclear radius formula is:

(a) R = R₀A^(1/3) ✅

(b) R = R₀A^(1/2)

(c) Random

(d) None

Explanation: Radius proportional to cube root of mass number, R₀ ≈ 1.2 fm.

Q65. Liquid drop model explains:

(a) Fission phenomena ✅

(b) Fusion phenomena

(c) Random

(d) None

Explanation: Treats nucleus like charged liquid drop, explains deformation and splitting.

Q66. Shell model explains:

(a) Magic numbers of stability ✅

(b) Fission

(c) Random

(d) None

Explanation: Certain nucleon numbers (2, 8, 20, 28, 50, 82, 126) give extra stability.

Q67. Magic numbers are:

(a) Nucleon numbers giving extra stability ✅

(b) Atomic numbers

(c) Random

(d) None

Explanation: Explained by shell model, nuclei with magic numbers are more stable.

Q68. Nuclear spin arises from:

(a) Intrinsic spin of nucleons ✅

(b) Orbital motion of electrons

(c) Random

(d) None

Explanation: Nucleons have intrinsic spin, contributing to nuclear angular momentum.

Q69. Nuclear magnetic moment arises from:

(a) Spin and orbital motion of nucleons ✅

(b) Electron spin

(c) Random

(d) None

Explanation: Combination of spin and orbital contributions of protons and neutrons.

Q70. Radioactive tracers are used in:

(a) Medical imaging and industry ✅

(b) Cooking

(c) Random

(d) None

Explanation: Isotopes like Tc-99m used in diagnostic imaging.

Q71. Radiation therapy uses:

(a) Gamma rays and beta particles ✅

(b) Alpha particles only

(c) Random

(d) None

Explanation: High-energy radiation destroys cancer cells.

Q72. Radiation units include:

(a) Becquerel, Gray, Sievert ✅

(b) Joule, Watt

(c) Random

(d) None

Explanation: Becquerel measures activity, Gray measures absorbed dose, Sievert measures biological effect.

Q73. Biological effect of radiation depends on:

(a) Type, energy, dose, exposure time ✅

(b) Only dose

(c) Random

(d) None

Explanation: Different radiations have different penetration and damage potential.

Q74. Geiger-Müller counter detects:

(a) Ionizing radiation ✅

(b) Sound waves

(c) Random

(d) None

Explanation: Gas-filled detector counts radiation pulses.

Q75. Scintillation counter works by:

(a) Light flashes from radiation in crystal ✅

(b) Sound detection

(c) Random

(d) None

Explanation: Radiation excites scintillator material, producing light detected by photomultiplier.

Q76. Cloud chamber detects:

(a) Ionizing radiation tracks ✅

(b) Sound waves

(c) Random

(d) None

Explanation: Radiation ionizes vapor, forming visible tracks of charged particles.

Q77. Bubble chamber works by:

(a) Superheated liquid forming bubbles along particle paths ✅

(b) Gas ionization

(c) Random

(d) None

Explanation: Charged particles leave trails of bubbles in liquid hydrogen.

Q78. Cyclotron accelerates:

(a) Charged particles using magnetic and electric fields ✅

(b) Neutral particles

(c) Random

(d) None

Explanation: Alternating electric field accelerates particles, magnetic field bends them in circular path.

Q79. Synchrotron accelerates particles by:

(a) Varying magnetic field with particle speed ✅

(b) Constant magnetic field

(c) Random

(d) None

Explanation: Synchronizes magnetic field with particle velocity, allowing high energies.

Q80. Linear accelerator (LINAC) accelerates particles by:

(a) Series of drift tubes with alternating voltage ✅

(b) Magnetic confinement

(c) Random

(d) None

Explanation: Particles gain energy in straight line through successive accelerating gaps.

Q81. Nuclear reaction detectors include:

(a) Geiger counter, scintillation counter, cloud chamber ✅

(b) Thermometer

(c) Random

(d) None

Explanation: These detect radiation via ionization, light flashes, or tracks.

Q82. Radiation dose unit Gray measures:

(a) Energy absorbed per kg ✅

(b) Biological effect

(c) Random

(d) None

Explanation: 1 Gray = 1 Joule/kg absorbed dose.

Q83. Radiation dose unit Sievert measures:

(a) Biological effect of radiation ✅

(b) Energy absorbed

(c) Random

(d) None

Explanation: Accounts for type of radiation and biological damage.

Q84. Becquerel measures:

(a) Activity of radioactive source ✅

(b) Absorbed dose

(c) Random

(d) None

Explanation: 1 Bq = 1 disintegration per second.

Q85. Curie is:

(a) Older unit of activity ✅

(b) Unit of dose

(c) Random

(d) None

Explanation: 1 Curie = 3.7 × 10¹⁰ disintegrations per second.

Q86. Radiation shielding materials include:

(a) Lead, concrete ✅

(b) Wood

(c) Random

(d) None

Explanation: Dense materials absorb radiation effectively.

Q87. Biological effect of radiation depends on:

(a) Type, energy, dose, exposure time ✅

(b) Only dose

(c) Random

(d) None

Explanation: Different radiations have different penetration and damage potential.

Q88. Acute radiation syndrome occurs due to:

(a) High dose exposure in short time ✅

(b) Low dose exposure

(c) Random

(d) None

Explanation: Causes nausea, fatigue, organ damage.

Q89. Chronic radiation exposure leads to:

(a) Cancer, genetic mutations ✅

(b) Immediate death

(c) Random

(d) None

Explanation: Long-term low dose exposure increases risk of cancer.

Q90. Nuclear medicine uses:

(a) Radioisotopes for diagnosis and therapy ✅

(b) Cooking

(c) Random

(d) None

Explanation: Tc-99m used in imaging, I-131 in thyroid treatment.

Q91. PET scan uses:

(a) Positron-emitting isotopes ✅

(b) Alpha emitters

(c) Random

(d) None

Explanation: Detects gamma rays from positron annihilation, mapping metabolic activity.

Q92. MRI uses:

(a) Nuclear magnetic resonance ✅

(b) Radioactive isotopes

(c) Random

(d) None

Explanation: Strong magnetic fields and radio waves produce detailed body images.

Q93. Radiation therapy targets:

(a) Cancer cells ✅

(b) Healthy cells

(c) Random

(d) None

Explanation: High-energy radiation destroys malignant cells while sparing normal tissue.

Q94. Nuclear waste is:

(a) Radioactive byproducts of reactors ✅

(b) Non-radioactive material

(c) Random

(d) None

Explanation: Requires safe storage and disposal due to long half-lives.

Q95. Nuclear waste disposal methods include:

(a) Deep geological storage ✅

(b) Surface dumping

(c) Random

(d) None

Explanation: Isolates waste from environment for thousands of years.

Q96. Nuclear safeguards ensure:

(a) Safe use of nuclear materials ✅

(b) Unlimited use

(c) Random

(d) None

Explanation: Prevent misuse, ensure safety and non-proliferation.

Q97. Nuclear proliferation refers to:

(a) Spread of nuclear weapons technology ✅

(b) Peaceful use of nuclear energy

(c) Random

(d) None

Explanation: International treaties aim to limit proliferation.

Q98. International Atomic Energy Agency (IAEA) role is:

(a) Promote safe, peaceful nuclear use ✅

(b) Build weapons

(c) Random

(d) None

Explanation: Oversees safety, security, and peaceful applications globally.

Q99. Nuclear fusion research aims at:

(a) Clean, limitless energy ✅

(b) Weapon development

(c) Random

(d) None

Explanation: Fusion produces minimal waste, abundant fuel, and no greenhouse gases.

Q100. ITER project is:

(a) International fusion research reactor ✅

(b) Fission reactor

(c) Random

(d) None

Explanation: Large-scale tokamak in France, aims to demonstrate feasibility of fusion power.

Q101. Ionization chamber detects radiation by:

(a) Measuring ion pairs produced ✅

(b) Measuring sound

(c) Random

(d) None

Explanation: Radiation ionizes gas inside chamber; current proportional to radiation intensity.

Q102. Proportional counter differs from GM counter because:

(a) Output pulse proportional to energy of radiation ✅

(b) Output pulse always same

(c) Random

(d) None

Explanation: Useful for energy spectroscopy of particles.

Q103. Neutrinos are:

(a) Neutral, nearly massless particles ✅

(b) Charged particles

(c) Random

(d) None

Explanation: Produced in beta decay, interact weakly with matter.

Q104. Antineutrinos are emitted in:

(a) Beta-minus decay ✅

(b) Beta-plus decay

(c) Random

(d) None

Explanation: Neutron → proton + electron + antineutrino.

Q105. Neutrinos are emitted in:

(a) Beta-plus decay ✅

(b) Alpha decay

(c) Random

(d) None

Explanation: Proton → neutron + positron + neutrino.

Q106. Conservation laws in nuclear reactions include:

(a) Energy, momentum, charge, nucleon number ✅

(b) Only energy

(c) Random

(d) None

Explanation: All fundamental conservation laws hold true.

Q107. Pair production occurs when:

(a) Gamma photon converts into electron-positron pair ✅

(b) Neutron splits

(c) Random

(d) None

Explanation: Requires photon energy > 1.022 MeV.

Q108. Annihilation occurs when:

(a) Electron and positron combine to produce photons ✅

(b) Proton and neutron combine

(c) Random

(d) None

Explanation: Produces two gamma photons of 0.511 MeV each.

Q109. Nuclear reaction cross-section unit is:

(a) Barn ✅

(b) Gray

(c) Random

(d) None

Explanation: 1 barn = 10⁻²⁸ m², measures probability of reaction.

Q110. Neutron moderation is important because:

(a) Thermal neutrons more effective in fission ✅

(b) Fast neutrons more effective

(c) Random

(d) None

Explanation: Slow neutrons increase probability of fission in U-235.

Q111. Heavy water is used as:

(a) Moderator ✅

(b) Fuel

(c) Random

(d) None

Explanation: D₂O slows down neutrons without absorbing them.

Q112. Graphite is used as:

(a) Moderator ✅

(b) Fuel

(c) Random

(d) None

Explanation: Carbon slows neutrons effectively.

Q113. Control rods regulate:

(a) Neutron population ✅

(b) Proton population

(c) Random

(d) None

Explanation: Cadmium or boron rods absorb excess neutrons.

Q114. Criticality in reactor means:

(a) Chain reaction is self-sustaining ✅

(b) Chain reaction stops

(c) Random

(d) None

Explanation: Achieved when neutron production equals neutron loss.

Q115. Subcritical reactor means:

(a) Chain reaction dies out ✅

(b) Chain reaction grows

(c) Random

(d) None

Explanation: Neutron population decreases with time.

Q116. Supercritical reactor means:

(a) Neutron population increases rapidly ✅

(b) Neutron population decreases

(c) Random

(d) None

Explanation: Leads to uncontrolled chain reaction.

Q117. Breeder reactor produces:

(a) More fissile material than consumed ✅

(b) Less fissile material

(c) Random

(d) None

Explanation: Converts fertile isotopes into fissile ones.

Q118. Fusion fuel candidates include:

(a) Deuterium and tritium ✅

(b) Uranium

(c) Random

(d) None

Explanation: D-T fusion most feasible, requires high temperature.

Q119. Fusion releases energy because:

(a) Binding energy per nucleon increases ✅

(b) Binding energy decreases

(c) Random

(d) None

Explanation: Light nuclei combine to form more stable heavier nuclei.

Q120. Tokamak confines plasma using:

(a) Magnetic fields ✅

(b) Electric fields

(c) Random

(d) None

Explanation: Toroidal magnetic field traps plasma for fusion.

Q121. ITER project aims to:

(a) Demonstrate feasibility of fusion power ✅

(b) Build fission reactor

(c) Random

(d) None

Explanation: International collaboration building large tokamak in France.

Q122. Nuclear waste is dangerous because:

(a) Long half-life and radiation ✅

(b) Short half-life

(c) Random

(d) None

Explanation: Requires safe storage and disposal.

Q123. Deep geological storage is used for:

(a) Nuclear waste disposal ✅

(b) Fuel storage

(c) Random

(d) None

Explanation: Isolates waste from environment for thousands of years.

Q124. Nuclear safeguards ensure:

(a) Safe, peaceful use of nuclear materials ✅

(b) Unlimited use

(c) Random

(d) None

Explanation: Prevent misuse and proliferation.

Q125. Nuclear proliferation refers to:

(a) Spread of nuclear weapons technology ✅

(b) Peaceful use of nuclear energy

(c) Random

(d) None

Explanation: International treaties aim to limit proliferation.

Q126. Nuclear binding energy is:

(a) Energy required to separate nucleons ✅

(b) Energy to separate electrons

(c) Random

(d) None

Explanation: Binding energy holds nucleus together; higher binding energy means greater stability.

Q127. Mass defect arises because:

(a) Mass of nucleus < sum of nucleon masses ✅

(b) Mass of nucleus > sum of nucleon masses

(c) Random

(d) None

Explanation: Missing mass converted into binding energy via E = mc².

Q128. Binding energy per nucleon indicates:

(a) Stability of nucleus ✅

(b) Instability

(c) Random

(d) None

Explanation: Higher binding energy per nucleon means more stable nucleus.

Q129. Fission of U-235 is triggered by:

(a) Thermal neutrons ✅

(b) Fast neutrons

(c) Random

(d) None

Explanation: Slow neutrons increase probability of fission.

Q130. Fusion of deuterium and tritium produces:

(a) Helium and neutron ✅

(b) Uranium

(c) Random

(d) None

Explanation: D + T → He-4 + neutron + energy.

Q131. Nuclear chain reaction requires:

(a) Critical mass ✅

(b) Subcritical mass

(c) Random

(d) None

Explanation: Minimum mass ensures neutrons sustain reaction.

Q132. Moderator in reactor slows:

(a) Neutrons ✅

(b) Protons

(c) Random

(d) None

Explanation: Graphite or heavy water reduces neutron speed.

Q133. Control rods absorb:

(a) Excess neutrons ✅

(b) Protons

(c) Random

(d) None

Explanation: Cadmium or boron rods regulate reaction rate.

Q134. Fast breeder reactor produces:

(a) More fissile material ✅

(b) Less fissile material

(c) Random

(d) None

Explanation: Converts fertile isotopes like U-238 into Pu-239.

Q135. Fusion in stars occurs due to:

(a) High temperature and pressure ✅

(b) Low temperature

(c) Random

(d) None

Explanation: Overcomes Coulomb barrier, enabling hydrogen fusion.

Q136. Proton-proton chain converts:

(a) Hydrogen into helium ✅

(b) Uranium into plutonium

(c) Random

(d) None

Explanation: Main fusion process in Sun.

Q137. CNO cycle uses:

(a) Carbon, nitrogen, oxygen as catalysts ✅

(b) Hydrogen only

(c) Random

(d) None

Explanation: Dominant in massive stars.

Q138. Tokamak confines plasma with:

(a) Magnetic fields ✅

(b) Electric fields

(c) Random

(d) None

Explanation: Toroidal magnetic field traps plasma for fusion.

Q139. ITER project is:

(a) International fusion research reactor ✅

(b) Fission reactor

(c) Random

(d) None

Explanation: Large-scale tokamak in France.

Q140. Nuclear waste hazard is due to:

(a) Long half-life radiation ✅

(b) Short half-life

(c) Random

(d) None

Explanation: Requires safe disposal methods.

Q141. Deep geological storage isolates:

(a) Nuclear waste ✅

(b) Fuel

(c) Random

(d) None

Explanation: Keeps waste away from environment for thousands of years.

Q142. Nuclear safeguards prevent:

(a) Misuse of nuclear materials ✅

(b) Unlimited use

(c) Random

(d) None

Explanation: Ensure safety and non-proliferation.

Q143. Nuclear proliferation means:

(a) Spread of nuclear weapons technology ✅

(b) Peaceful use

(c) Random

(d) None

Explanation: Controlled by international treaties.

Q144. IAEA role is:

(a) Promote safe, peaceful nuclear use ✅

(b) Build weapons

(c) Random

(d) None

Explanation: Oversees safety and peaceful applications globally.

Q145. Radiation units include:

(a) Becquerel, Gray, Sievert ✅

(b) Joule, Watt

(c) Random

(d) None

Explanation: Becquerel measures activity, Gray absorbed dose, Sievert biological effect.

Q146. Geiger-Müller counter detects:

(a) Ionizing radiation ✅

(b) Sound waves

(c) Random

(d) None

Explanation: Gas-filled detector counts radiation pulses.

Q147. Scintillation counter detects radiation via:

(a) Light flashes in crystal ✅

(b) Sound detection

(c) Random

(d) None

Explanation: Radiation excites scintillator, producing light detected by photomultiplier.

Q148. Cloud chamber shows:

(a) Tracks of charged particles ✅

(b) Sound waves

(c) Random

(d) None

Explanation: Ionization of vapor forms visible trails.

Q149. Bubble chamber shows:

(a) Bubbles along particle paths ✅

(b) Sound waves

(c) Random

(d) None

Explanation: Charged particles leave trails in superheated liquid.

Q150. Cyclotron accelerates:

(a) Charged particles in circular path ✅

(b) Neutral particles

(c) Random

(d) None

Explanation: Alternating electric field accelerates particles, magnetic field bends them.

Q151. Linear accelerator (LINAC) accelerates particles by:

(a) Series of drift tubes with alternating voltage ✅

(b) Magnetic confinement

(c) Random

(d) None

Explanation: Particles gain energy in straight line through successive accelerating gaps.

Q152. Synchrotron accelerates particles by:

(a) Varying magnetic field with particle speed ✅

(b) Constant magnetic field

(c) Random

(d) None

Explanation: Synchronizes magnetic field with particle velocity, allowing very high energies.

Q153. Betatron accelerates:

(a) Electrons using changing magnetic field ✅

(b) Protons

(c) Random

(d) None

Explanation: Induced electric field from changing magnetic flux accelerates electrons.

Q154. Nuclear reaction rate depends on:

(a) Cross-section and particle flux ✅

(b) Only mass

(c) Random

(d) None

Explanation: Rate = σ × flux × number of target nuclei.

Q155. Neutron capture leads to:

(a) Formation of heavier isotope ✅

(b) Splitting nucleus

(c) Random

(d) None

Explanation: Absorbed neutron increases mass number by one.

Q156. Radiocarbon dating uses:

(a) C-14 isotope ✅

(b) U-238 isotope

(c) Random

(d) None

Explanation: Measures age of organic materials using half-life of carbon-14.

Q157. Half-life of C-14 is:

(a) ~5730 years ✅

(b) ~100 years

(c) Random

(d) None

Explanation: Used in dating archaeological samples.

Q158. Uranium-238 dating is used for:

(a) Geological samples ✅

(b) Organic samples

(c) Random

(d) None

Explanation: Long half-life (~4.5 billion years) suitable for rocks.

Q159. Nuclear medicine uses isotopes like:

(a) Tc-99m, I-131 ✅

(b) U-235

(c) Random

(d) None

Explanation: Tc-99m for imaging, I-131 for thyroid treatment.

Q160. PET scan detects:

(a) Gamma rays from positron annihilation ✅

(b) Alpha particles

(c) Random

(d) None

Explanation: Positron emitters produce annihilation photons detected in scan.

Q161. MRI principle is:

(a) Nuclear magnetic resonance ✅

(b) Radioactive decay

(c) Random

(d) None

Explanation: Uses strong magnetic fields and radio waves for imaging.

Q162. Radiation therapy uses:

(a) Gamma rays, X-rays, electrons ✅

(b) Sound waves

(c) Random

(d) None

Explanation: High-energy radiation destroys cancer cells.

Q163. Radiation damage depends on:

(a) Dose, type, exposure time ✅

(b) Only dose

(c) Random

(d) None

Explanation: Different radiations have different biological effects.

Q164. Acute radiation syndrome occurs due to:

(a) High dose in short time ✅

(b) Low dose

(c) Random

(d) None

Explanation: Causes nausea, fatigue, organ damage.

Q165. Chronic radiation exposure leads to:

(a) Cancer, genetic mutations ✅

(b) Immediate death

(c) Random

(d) None

Explanation: Long-term low dose exposure increases cancer risk.

Q166. Nuclear waste hazard is due to:

(a) Long half-life isotopes ✅

(b) Short half-life isotopes

(c) Random

(d) None

Explanation: Requires safe disposal methods.

Q167. Deep geological storage isolates:

(a) Nuclear waste ✅

(b) Fuel

(c) Random

(d) None

Explanation: Keeps waste away from environment for thousands of years.

Q168. Nuclear safeguards prevent:

(a) Misuse of nuclear materials ✅

(b) Unlimited use

(c) Random

(d) None

Explanation: Ensure safety and non-proliferation.

Q169. Nuclear proliferation means:

(a) Spread of nuclear weapons technology ✅

(b) Peaceful use

(c) Random

(d) None

Explanation: Controlled by international treaties.

Q170. IAEA role is:

(a) Promote safe, peaceful nuclear use ✅

(b) Build weapons

(c) Random

(d) None

Explanation: Oversees safety and peaceful applications globally.

Q171. Fusion research aims at:

(a) Clean, limitless energy ✅

(b) Weapon development

(c) Random

(d) None

Explanation: Fusion produces minimal waste, abundant fuel, no greenhouse gases.

Q172. ITER project is:

(a) International fusion research reactor ✅

(b) Fission reactor

(c) Random

(d) None

Explanation: Large-scale tokamak in France.

Q173. Tokamak confines plasma using:

(a) Magnetic fields ✅

(b) Electric fields

(c) Random

(d) None

Explanation: Toroidal magnetic field traps plasma for fusion.

Q174. Fusion fuel candidates include:

(a) Deuterium and tritium ✅

(b) Uranium

(c) Random

(d) None

Explanation: D-T fusion most feasible, requires high temperature.

Q175. Fusion releases energy because:

(a) Binding energy per nucleon increases ✅

(b) Binding energy decreases

(c) Random

(d) None

Explanation: Light nuclei combine to form more stable heavier nuclei.

Q176. Pair production requires photon energy:

(a) Greater than 1.022 MeV ✅

(b) Less than 1 MeV

(c) Random

(d) None

Explanation: Gamma photon converts into electron-positron pair; threshold equals 2 × rest mass energy of electron.

Q177. Annihilation of electron and positron produces:

(a) Two gamma photons of 0.511 MeV each ✅

(b) One neutron

(c) Random

(d) None

Explanation: Mass converts entirely into energy, conserving momentum.

Q178. Nuclear reaction rate formula is:

(a) Rate = σ × flux × number of target nuclei ✅

(b) Rate = mass × velocity

(c) Random

(d) None

Explanation: Depends on cross-section and incident particle flux.

Q179. Neutron activation analysis is used for:

(a) Detecting trace elements ✅

(b) Measuring mass

(c) Random

(d) None

Explanation: Irradiated sample becomes radioactive; emitted radiation identifies elements.

Q180. Radiocarbon dating is effective for:

(a) Organic samples up to ~50,000 years ✅

(b) Geological samples billions of years old

(c) Random

(d) None

Explanation: Uses half-life of C-14 (~5730 years).

Q181. Uranium-238 dating is effective for:

(a) Geological samples billions of years old ✅

(b) Organic samples

(c) Random

(d) None

Explanation: Half-life ~4.5 billion years, suitable for rocks.

Q182. Nuclear spin contributes to:

(a) Magnetic moment of nucleus ✅

(b) Electric charge

(c) Random

(d) None

Explanation: Spin and orbital motion of nucleons produce magnetic moment.

Q183. Shell model explains:

(a) Magic numbers of stability ✅

(b) Fission

(c) Random

(d) None

Explanation: Certain nucleon numbers (2, 8, 20, 28, 50, 82, 126) give extra stability.

Q184. Liquid drop model explains:

(a) Fission phenomena ✅

(b) Fusion phenomena

(c) Random

(d) None

Explanation: Treats nucleus like charged liquid drop, explains deformation and splitting.

Q185. Nuclear density is:

(a) Nearly constant for all nuclei ✅

(b) Varies with mass number

(c) Random

(d) None

Explanation: Mass ∝ A and volume ∝ A, so density remains constant (~2.3 × 10¹⁷ kg/m³).

Q186. Nuclear radius formula is:

(a) R = R₀A^(1/3) ✅

(b) R = R₀A^(1/2)

(c) Random

(d) None

Explanation: Radius proportional to cube root of mass number, R₀ ≈ 1.2 fm.

Q187. Nuclear force properties include:

(a) Strong, short-range, saturating ✅

(b) Weak, long-range

(c) Random

(d) None

Explanation: Acts only between nearest nucleons, independent of charge.

Q188. Saturation of nuclear force means:

(a) Each nucleon interacts with limited neighbors ✅

(b) Each nucleon interacts with all

(c) Random

(d) None

Explanation: Explains constant nuclear density.

Q189. Nuclear fusion releases energy because:

(a) Binding energy per nucleon increases ✅

(b) Binding energy decreases

(c) Random

(d) None

Explanation: Light nuclei combine to form more stable heavier nuclei.

Q190. Nuclear fission releases energy because:

(a) Binding energy per nucleon increases ✅

(b) Binding energy decreases

(c) Random

(d) None

Explanation: Heavy nuclei split into medium nuclei with higher binding energy per nucleon.

Q191. Fusion fuel candidates include:

(a) Deuterium and tritium ✅

(b) Uranium

(c) Random

(d) None

Explanation: D-T fusion most feasible, requires high temperature.

Q192. Tokamak confines plasma using:

(a) Magnetic fields ✅

(b) Electric fields

(c) Random

(d) None

Explanation: Toroidal magnetic field traps plasma for fusion.

Q193. ITER project aims to:

(a) Demonstrate feasibility of fusion power ✅

(b) Build fission reactor

(c) Random

(d) None

Explanation: International collaboration building large tokamak in France.

Q194. Nuclear waste hazard is due to:

(a) Long half-life isotopes ✅

(b) Short half-life isotopes

(c) Random

(d) None

Explanation: Requires safe disposal methods.

Q195. Deep geological storage isolates:

(a) Nuclear waste ✅

(b) Fuel

(c) Random

(d) None

Explanation: Keeps waste away from environment for thousands of years.

Q196. Nuclear safeguards prevent:

(a) Misuse of nuclear materials ✅

(b) Unlimited use

(c) Random

(d) None

Explanation: Ensure safety and non-proliferation.

Q197. Nuclear proliferation means:

(a) Spread of nuclear weapons technology ✅

(b) Peaceful use

(c) Random

(d) None

Explanation: Controlled by international treaties.

Q198. IAEA role is:

(a) Promote safe, peaceful nuclear use ✅

(b) Build weapons

(c) Random

(d) None

Explanation: Oversees safety and peaceful applications globally.

Q199. Fusion research aims at:

(a) Clean, limitless energy ✅

(b) Weapon development

(c) Random

(d) None

Explanation: Fusion produces minimal waste, abundant fuel, no greenhouse gases.

Q200. Applications of nuclear physics include:

(a) Power generation, medicine, imaging, industry ✅

(b) Cooking only

(c) Random

(d) None

Explanation: Nuclear physics underpins reactors, radiation therapy, PET scans, MRI, and industrial uses.