Q100. Under Rutherford’s atomic model, which description best fits the nucleus?
[RRB Group D (20 August 2026, Shift 1)]
(A) A broad negatively charged region
(B) A tiny, dense, positively charged centre
(C) A diffuse neutral cloud
(D) A shell consisting only of electrons
Answer: (B) A tiny, dense, positively charged centre
Explanation: Rutherford inferred a compact central nucleus from the rare large-angle deflections of alpha particles passing through thin metal foil. Almost all atomic mass is concentrated in this extremely small, positively charged region, whereas electrons occupy the surrounding space.
Q99. Which observation in Rutherford’s alpha-scattering experiment supported the conclusion that atoms are mostly empty space?
[RRB Group D (14 August 2026, Shift 2)]
(A) Every alpha particle was absorbed
(B) The foil disintegrated
(C) Electrons carried a positive charge
(D) Only a small proportion of alpha particles were deflected
Answer: (D) Only a small proportion of alpha particles were deflected
Explanation: Most alpha particles travelled through the thin gold sheet almost undeflected. Consequently, most atomic volume could not contain dense matter. The few strongly deflected particles revealed a tiny central nucleus with concentrated positive charge and mass.
Q98. Which pair represents isobars?
[RRB Group D (10 August 2026, Shift 1)]
(A) Sodium-23 and magnesium-24
(B) Calcium-40 and argon-40
(C) Chlorine-35 and chlorine-37
(D) Carbon-12 and carbon-14
Answer: (B) Calcium-40 and argon-40
Explanation: Calcium-40 has 20 protons and argon-40 has 18. Despite the difference in atomic number, both nuclei contain 40 nucleons. The other same-element pairs are isotopes rather than isobars because their proton numbers coincide.
Q97. Which type of electric charge does a proton carry?
[RRB Group D (14 August 2026, Shift 3)]
(A) No charge
(B) Negative charge
(C) Variable charge
(D) Positive charge
Answer: (D) Positive charge
Explanation: A proton has one positive elementary charge, approximately 1.602 × 10⁻¹⁹ coulomb. Protons reside inside the atomic nucleus with neutral neutrons. The count of protons determines the atomic number and identity of each chemical element.
Q96. Approximately what is the radius of an atom in metres?
[RRB Group D (3 February 2026, Shift 3)]
(A) 10¹⁵
(B) 10⁻¹⁰
(C) 10¹⁰
(D) 10⁻⁵
Answer: (B) 10⁻¹⁰
Explanation: A typical atomic radius is on the order of one ångström, corresponding to 10⁻¹⁰ metre. The nucleus is much smaller, around 10⁻¹⁵ metre in radius, explaining why most of an atom is empty space.
Q95. Which experiment furnished evidence for the atomic nucleus?
[RRB NTPC Graduate CBT-I (17 March 2026, Shift 3)]
(A) Gold-foil scattering experiment
(B) Canal-ray experiment
(C) Cathode-ray experiment
(D) Oil-drop experiment
Answer: (A) Gold-foil scattering experiment
Explanation: Rutherford’s team directed alpha particles toward thin gold foil. Most passed through, but some underwent large deflections. The observations demonstrated that nearly all atomic mass and positive charge occupy a very small nucleus.
Q94. Who put forward the nuclear model after interpreting gold-foil scattering?
[RRB NTPC Graduate CBT-I (18 March 2026, Shift 3)]
(A) J. J. Thomson
(B) Niels Bohr
(C) John Dalton
(D) Ernest Rutherford
Answer: (D) Ernest Rutherford
Explanation: Ernest Rutherford proposed the nuclear model in 1911 after alpha-scattering measurements. His interpretation replaced Thomson’s positive-sphere model with a small, massive, positively charged centre. Bohr later introduced quantized electronic orbits to address atomic stability.
Q93. Which legislation approved in 2025 consolidated India’s civilian nuclear framework and permitted private participation?
[RRB NTPC Graduate CBT-I (22 March 2026, Shift 3)]
(A) Atomic Energy Reform Bill
(B) Civil Nuclear Governance Bill
(C) SHANTI Bill
(D) National Nuclear Expansion Bill
Answer: (C) SHANTI Bill
Explanation: The Sustainable Harnessing and Advancement of Nuclear Energy for Transforming India legislation, commonly called SHANTI, was designed to update the civil nuclear regulatory framework. The examination tested identification of the named law, not the physics of fission.
Q92. Under the SHANTI Act, 2025, which regulatory body was specified?
[RRB NTPC Graduate CBT-II (10 July 2026)]
(A) Atomic Energy Regulatory Board
(B) Nuclear Power Development Board
(C) Central Radiation Monitoring Board
(D) National Nuclear Safety Board
Answer: (A) Atomic Energy Regulatory Board
Explanation: The question identifies the Atomic Energy Regulatory Board as the nuclear oversight body associated with the SHANTI framework. Nuclear regulation concerns licensing, radiation protection and safety requirements rather than the production of electricity itself.
Q91. With which country did India announce a partnership on advanced and small modular reactors in February 2025?
[RRB NTPC Undergraduate CBT-I (8 May 2026, Shift 3)]
(A) France
(B) Japan
(C) Russia
(D) United States
Answer: (A) France
Explanation: India and France announced cooperation on advanced nuclear reactors and small modular reactor technologies. Such reactors aim for more flexible deployment of nuclear generation. The question tests a dated bilateral nuclear-technology agreement rather than a fundamental nuclear reaction.
Q90. Which subatomic particle was discovered by James Chadwick in 1932?
[SSC MTS 2025 paper (held 11 February 2026, Shift 1)]
(A) Proton
(B) Electron
(C) Neutron
(D) Alpha particle
Answer: (C) Neutron
Explanation: James Chadwick established the existence of the electrically neutral neutron through experiments involving radiation from beryllium. Neutrons have masses close to protons and, together with protons, constitute most of the atomic nucleus.
Q89. If chlorine-35 and chlorine-37 occur in approximately a 3:1 ratio, what is chlorine’s relative atomic mass?
[RRB Group D (18 August 2026, Shift 1)]
(A) 37 u
(B) 36 u
(C) 35.5 u
(D) 34.5 u
Answer: (C) 35.5 u
Explanation: The average is weighted by isotopic abundance: (35 × 0.75) + (37 × 0.25) = 35.5 u. Individual isotopes have nearly integral mass numbers, but a naturally occurring elemental sample contains a mixture.
Q88. Which nuclear decay increases atomic number by one without changing mass number?
[SSC CGL (24 September 2025, Shift 3)]
(A) Alpha emission
(B) Beta-minus emission
(C) Beta-plus emission
(D) Gamma emission
Answer: (B) Beta-minus emission
Explanation: In beta-minus decay, one neutron becomes a proton while an electron and an antineutrino are emitted. Proton count therefore rises by one, but the total number of nucleons and the mass number remain unchanged.
Q87. What happens to proton number during beta-plus decay?
[SSC CGL (22 September 2025, Shift 3)]
(A) It falls by one without a change in mass number
(B) It rises by one without a mass change
(C) Both proton and mass numbers decline
(D) Proton number falls by two and mass number by four
Answer: (A) It falls by one without a change in mass number
Explanation: A proton converts into a neutron, releasing a positron and a neutrino during beta-plus decay. Therefore atomic number decreases by one while mass number remains constant. The weak interaction mediates this nuclear transformation.
Q86. How does the total mass of fission products compare with that of the original reactants?
[SSC CGL (22 September 2025, Shift 2)]
(A) Greater
(B) Exactly equal
(C) Slightly smaller
(D) Only temperature dependent
Answer: (C) Slightly smaller
Explanation: In energy-releasing fission, the total rest mass of the final products is slightly less than the initial rest mass. The missing mass appears as kinetic energy and radiation according to Einstein’s relationship E = mc².
Q85. Which statement is NOT generally a property of the nuclear force?
[RRB JE CBT-II CMA (22 April 2025, Shift 2)]
(A) It is attractive at ordinary nuclear distances
(B) It is much stronger than Coulomb repulsion at short range
(C) It shows saturation
(D) Its strength depends strongly on a nucleon’s electric charge
Answer: (D) Its strength depends strongly on a nucleon’s electric charge
Explanation: The residual strong force between nucleons is approximately charge-independent: proton–proton, neutron–neutron and proton–neutron interactions share similar strong components. It is powerful over femtometre distances and demonstrates saturation because each nucleon interacts mainly with nearby nucleons.
Q84. What is the splitting of a heavy nucleus into smaller nuclei with energy release called?
[RRB JE CBT-II CMA (22 April 2025, Shift 1)]
(A) Fusion
(B) Ordinary radioactive decay only
(C) Fission
(D) Ionization
Answer: (C) Fission
Explanation: Nuclear fission divides a heavy atomic nucleus into smaller fragments, commonly releasing neutrons and substantial energy. Its energy derives from increased binding energy per nucleon in the products. Controlled fission provides reactor heat.
Q83. A radionuclide has a 10-day half-life. When will 75% of the original amount have decayed?
[SSC Selection Post Graduate (29 August 2025, Shift 1)]
(A) 5 days
(B) 10 days
(C) 20 days
(D) 30 days
Answer: (C) 20 days
Explanation: After the first ten days, 50% remains. After a second ten-day half-life, only 25% remains; therefore 75% has decayed. The calculation uses exponential decay and assumes an unchanged decay probability.
Q82. Which listed carbon nuclide is radioactive?
[SSC JE Mechanical (6 December 2025, Shift 2)]
(A) Carbon-12
(B) Carbon-13
(C) Carbon-14
(D) Carbon-6
Answer: (C) Carbon-14
Explanation: Carbon-14 is unstable and undergoes beta-minus decay to nitrogen-14 with a half-life of about 5,730 years. It is produced in the atmosphere and used for dating once-living material through measurement of its residual activity.
Q81. Dubnium, an artificial radioactive element with atomic number 105, belongs to which group?
[SSC GD Constable (12 February 2025, Shift 2)]
(A) Group 3
(B) Group 7
(C) Group 5
(D) Group 11
Answer: (C) Group 5
Explanation: Dubnium, symbol Db, is a synthetic transactinide element with proton number 105. On the periodic table, it occupies Group 5, below tantalum. Its isotopes are radioactive and are usually produced in particle-accelerator experiments.
Q80. What nuclear-power capacity target did India announce for 2047 in its 2025–26 Union Budget?
[RRB Group D (8 December 2025, Shift 1)]
(A) 80 GW
(B) 100 GW
(C) 150 GW
(D) 50 GW
Answer: (B) 100 GW
Explanation: The Budget announced a long-term ambition of 100 gigawatts of nuclear generation capacity by 2047. This is a policy target, not an existing installed-capacity figure. Expanding nuclear power could provide low-carbon electricity when reactors operate safely.
Q79. What mission did the Union Budget 2025–26 announce for nuclear electricity development?
[RRB Group D (12 December 2025, Shift 2)]
(A) Hydropower Mission
(B) Nuclear Energy Mission
(C) Hydrogen Mission
(D) Electric Vehicle Mission
Answer: (B) Nuclear Energy Mission
Explanation: The Union Budget highlighted a Nuclear Energy Mission to expand clean firm power and support development of advanced reactors. A nuclear mission concerns reactor technology and power capacity, distinguishing it from hydrogen, hydroelectric and vehicle programmes.
Q78. Which power project listed below is nuclear rather than hydroelectric?
[RRB NTPC Undergraduate CBT-I (13 August 2025, Shift 2)]
(A) Koyna
(B) Tehri
(C) Kalpakkam
(D) Bhakra Nangal
Answer: (C) Kalpakkam
Explanation: Kalpakkam in Tamil Nadu hosts the Madras Atomic Power Station and nuclear research facilities. Koyna, Tehri and Bhakra Nangal are associated with hydropower. Nuclear stations convert heat from controlled fission into electrical power.
Q77. In which state is the Gorakhpur nuclear-power project, described as North India’s first such project?
[RRB NTPC Undergraduate CBT-I (8 September 2025, Shift 1)]
(A) Haryana
(B) Uttarakhand
(C) Punjab
(D) Himachal Pradesh
Answer: (A) Haryana
Explanation: The Gorakhpur Haryana Anu Vidyut Pariyojana is being developed in Fatehabad district of Haryana. It is planned around indigenous pressurised heavy-water reactor technology, which uses heavy water to moderate the neutron chain reaction.
Q76. What particles used in Rutherford’s experiment correspond to doubly charged helium nuclei?
[RRB Group D (17 December 2025, Shift 1)]
(A) Delta particles
(B) Gamma rays
(C) Beta particles
(D) Alpha particles
Answer: (D) Alpha particles
Explanation: An alpha particle is the helium-4 nucleus: two protons and two neutrons, carrying charge +2e. Rutherford used these relatively massive positive particles to probe the concentration of charge and mass inside atoms.
Q75. What number is identical in isotopes of the same chemical element?
[RRB Group D (29 December 2025, Shift 3)]
(A) Electrons in any ion
(B) Neutrons
(C) Protons
(D) Nuclear orbitals
Answer: (C) Protons
Explanation: Isotopes have the same atomic number, and therefore the same number of protons. They differ in neutron number and mass number. For example, carbon-12 and carbon-14 both contain six protons but different neutron counts.
Q74. Which observation remained unexplained by Rutherford’s planetary atomic model?
[RRB Group D (5 December 2025, Shift 3)]
(A) Why orbiting electrons do not radiate away their energy
(B) The existence of a positive nucleus
(C) Large-angle alpha scattering
(D) Why most alpha particles pass through foil
Answer: (A) Why orbiting electrons do not radiate away their energy
Explanation: Classical electrodynamics predicts that an accelerating electron in an orbit radiates energy and spirals inward. Rutherford’s model did not explain stable atoms. Bohr later proposed stationary energy states in which electrons do not continuously radiate.
Q73. Why is the standard atomic mass of chlorine near 35.5 rather than a whole number?
[RRB Group D (27 November 2025, Shift 1)]
(A) Its natural isotopic mixture
(B) Its atoms are ions
(C) A measurement mistake
(D) Chlorine is a compound
Answer: (A) Its natural isotopic mixture
Explanation: Natural chlorine consists chiefly of chlorine-35 and chlorine-37. Their approximate 3:1 abundances give a weighted average near 35.5. Individual isotope mass numbers are whole numbers even when the standard atomic weight is fractional.
Q72. What is the mass number associated with carbon-13?
[RRB Group D (4 December 2025, Shift 1)]
(A) 13
(B) 12
(C) 11
(D) 14
Answer: (A) 13
Explanation: Carbon-13 contains six protons and seven neutrons, giving mass number thirteen. Unlike carbon-14, carbon-13 is stable. Its actual atomic mass is close to, but not exactly, 13 unified atomic mass units.
Q71. Concerning radioisotope thermoelectric generators (RTGs), assess:
1. RTGs are miniature fission reactors.
2. They can power spacecraft systems.
3. Plutonium-238 can serve as the heat source.
Which are correct?
[UPSC Civil Services Preliminary Examination (2024)]
(A) 1 and 2 only
(B) 2 and 3 only
(C) 1 and 3 only
(D) 1, 2 and 3
Answer: (B) 2 and 3 only
Explanation: RTGs use heat from spontaneous radioactive decay, not a controlled fission chain reaction, to generate electricity. They power distant spacecraft where sunlight is weak. Plutonium-238 is a suitable heat source because its decay provides predictable thermal energy.
Q70. Regarding stellar evolution: Statement I says giant stars live longer than dwarf stars; Statement II says giant stars have faster nuclear reactions. Which assessment is right?
[UPSC Civil Services Preliminary Examination (2024)]
(A) Both true, II explains I
(B) Both true, II does not explain I
(C) I true, II false
(D) I false, II true
Answer: (D) I false, II true
Explanation: Very massive stars burn nuclear fuel much faster than lower-mass dwarf stars, despite having larger fuel reserves. Hence massive stars generally have shorter lifetimes. The increased rate of fusion makes the second statement true and the first false.
Q69. Which of these is NOT an essential component or function of a nuclear power-reactor system?
[UPSC NDA-I General Ability Test (21 April 2024)]
(A) Turbine
(B) Heat exchanger
(C) Device specifically meant to reduce carbon-dioxide emissions
(D) Reaction chamber
Answer: (C) Device specifically meant to reduce carbon-dioxide emissions
Explanation: A nuclear station has a reactor core, heat-transfer systems and usually a turbine-generator. Because fission itself emits little carbon dioxide during operation, a special carbon-dioxide-removal device is not a standard required part of the reactor system.
Q68. The Higgs boson has a rest mass nearest to which of these values?
[UPSC CDS-I General Knowledge (2024)]
(A) 0.5 MeV
(B) 900 MeV
(C) 100 GeV
(D) 1,000 GeV
Answer: (C) 100 GeV
Explanation: The Higgs boson has a measured mass near 125 GeV/c², so 100 GeV is the closest listed value. It is an elementary particle associated with the Higgs field, not a proton, neutron or radioactive nucleus.
Q67. Which of electron, proton, neutron and muon qualify as subatomic particles?
[UPSC CDS-I General Knowledge (2024)]
(A) Electron and muon only
(B) All four
(C) Proton and neutron only
(D) Electron, proton and neutron only
Answer: (B) All four
Explanation: Subatomic particles are smaller constituents or elementary particles relevant to atomic matter. Electrons, protons and neutrons are familiar examples, while the muon is a heavier lepton related to the electron. All four therefore qualify.
Q66. Which radiation has wavelengths below about 10⁻³ nanometre and is associated with radioactive decay?
[SSC CGL Tier-I (11 September 2024, Shift 1)]
(A) Gamma rays
(B) Infrared rays
(C) Microwaves
(D) Ultraviolet rays
Answer: (A) Gamma rays
Explanation: Gamma radiation consists of high-energy photons emitted in nuclear transitions or other energetic processes. Its exceptionally short wavelength corresponds to high photon energy. Unlike alpha and beta particles, gamma rays are electromagnetic radiation without electric charge.
Q65. The Narora nuclear electricity station is situated in which state?
[SSC CHSL Tier-I (5 July 2024, Shift 4)]
(A) Tamil Nadu
(B) Uttar Pradesh
(C) Maharashtra
(D) Karnataka
Answer: (B) Uttar Pradesh
Explanation: The Narora Atomic Power Station is in Bulandshahr district of Uttar Pradesh. Its reactors use nuclear fission to release heat, which ultimately drives a turbine-generator. Kalpakkam is in Tamil Nadu, whereas Tarapur is in Maharashtra.
Q64. Which isotope serves as a major fissile fuel in nuclear electricity stations?
[SSC CHSL Tier-I (11 July 2024, Shift 1)]
(A) Uranium-235
(B) Sodium-24
(C) Carbon-14
(D) Arsenic-74
Answer: (A) Uranium-235
Explanation: Uranium-235 can undergo fission after absorbing a neutron, releasing energy and additional neutrons. These emitted neutrons can sustain a controlled chain reaction. Carbon-14 is mainly known as a dating isotope, not reactor fuel.
Q63. For what discovery did Henri Becquerel share the 1903 Nobel Prize in Physics?
[SSC CHSL Tier-I (3 July 2024, Shift 3)]
(A) Spontaneous radioactivity
(B) Radon gas
(C) Diagnostic radiography
(D) Artificial transuranium elements
Answer: (A) Spontaneous radioactivity
Explanation: Henri Becquerel found that uranium compounds emitted penetrating radiation even without illumination. His discovery of spontaneous radioactivity earned him a share of the 1903 Physics Nobel Prize alongside Pierre and Marie Curie for related studies.
Q62. Which device accelerates electrically charged particles to high speeds?
[SSC CHSL Tier-I (5 July 2024, Shift 1)]
(A) Cyclotron
(B) Copatron
(C) Cosmotron
(D) Cryotron
Answer: (A) Cyclotron
Explanation: A cyclotron uses an alternating electric field to accelerate charged particles and a magnetic field to bend their trajectories. Such accelerators are used in nuclear research and production of medically useful isotopes. Neutral particles cannot be accelerated directly by electric fields.
Q61. What is uranium’s atomic number?
[SSC MTS (13 November 2024, Shift 3)]
(A) 104
(B) 94
(C) 90
(D) 92
Answer: (D) 92
Explanation: Uranium has atomic number 92, meaning each uranium nucleus contains 92 protons. Its naturally abundant isotopes include uranium-238 and uranium-235, which differ in neutron number and play different roles in nuclear fuel cycles.
Q60. Kakrapar Atomic Power Station is located in which Indian state?
[SSC MTS (12 November 2024, Shift 3)]
(A) Rajasthan
(B) Maharashtra
(C) Gujarat
(D) Tamil Nadu
Answer: (C) Gujarat
Explanation: The Kakrapar Atomic Power Station operates near Kakrapar in Gujarat. Its pressurised heavy-water reactors use heavy water for neutron moderation. Rajasthan Atomic Power Station is at Rawatbhata, which is a different location.
Q59. Statement I: India relies heavily on coal despite uranium deposits.
Statement II: Electricity generation requires uranium enriched to at least 60%.
Which is correct?
[UPSC Civil Services Preliminary Examination (2023)]
(A) Both true, II explains I
(B) Both true, II does not explain I
(C) I true, II false
(D) I false, II true
Answer: (C) I true, II false
Explanation: India has uranium resources but historically relies on coal for most electricity. The claim that reactor fuel must contain at least 60% uranium-235 is false; many commercial reactors use much lower enrichment, while Indian PHWRs can use natural uranium.
Q58. The hydrogen bomb and uranium fission bomb operate principally by which processes, respectively?
[UPSC CDS-I General Knowledge (2023)]
(A) Nuclear fusion and nuclear fission
(B) Fission and fusion
(C) Geothermal fission and fusion
(D) Geothermal fusion and fission
Answer: (A) Nuclear fusion and nuclear fission
Explanation: Thermonuclear weapons derive major energy from fusion of light nuclei, generally initiated using fission. A uranium atomic bomb relies primarily on rapid, uncontrolled fission of fissile uranium nuclei. The processes differ in whether nuclei combine or split.
Q57. What Group 18 gas can arise from natural radioactive decay in uranium-bearing soils and rocks?
[SSC CPO Paper-I (5 October 2023, Shift 1)]
(A) Oganesson
(B) Krypton
(C) Radon
(D) Neon
Answer: (C) Radon
Explanation: Radon is a radioactive noble gas formed during decay chains of uranium and radium in rocks and soil. Because it is a gas, it can migrate into buildings. Prolonged exposure to radon decay products increases lung-cancer risk.
Q56. Which radioactive element occupies position 87 in the periodic table and has a short-lived common isotope?
[SSC CHSL Tier-I (10 August 2023, Shift 4)]
(A) Meitnerium
(B) Dubnium
(C) Seaborgium
(D) Francium
Answer: (D) Francium
Explanation: Francium has atomic number 87 and is an alkali metal. Its isotopes are highly unstable; francium-223 has a half-life of roughly 22 minutes. Consequently, francium is exceptionally rare in naturally occurring accessible quantities.
Q55. The radioactive synthetic element seaborgium has which atomic number?
[SSC CGL Tier-I (20 July 2023, Shift 2)]
(A) 110
(B) 106
(C) 102
(D) 113
Answer: (B) 106
Explanation: Seaborgium is designated Sg and has atomic number 106. Named after nuclear chemist Glenn T. Seaborg, it is artificially produced and highly radioactive. An atomic number of 106 means every seaborgium nucleus contains 106 protons.
Q54. How many chemical elements comprise the actinide series?
[SSC MTS 2022 exam cycle (held 20 June 2023, Shift 3)]
(A) 18
(B) 12
(C) 9
(D) 15
Answer: (D) 15
Explanation: The actinide series contains fifteen elements, conventionally actinium through lawrencium. They are f-block elements associated with partially filled 5f orbitals, and all are radioactive. Uranium, thorium and plutonium are especially relevant to nuclear technology.
Q53. A nuclear reactor in a nuclear station is analogous to which part of a coal-fired thermal plant?
[WBCS Mains 2021 exam (held May 2022), Paper IV]
(A) Boiler
(B) Turbine
(C) Electric generator
(D) Exhaust chimney
Answer: (A) Boiler
Explanation: The nuclear reactor is the heat source, analogous to the boiler or furnace in a conventional thermal station. Fission heat is carried away by coolant and ultimately drives a steam cycle connected to an electrical generator.
Q52. What reaction produces the Sun’s radiant energy?
[WBCS Mains 2021 exam (held May 2022), Paper IV]
(A) Nuclear fission
(B) Ordinary disintegration
(C) Photoelectric emission
(D) Nuclear fusion
Answer: (D) Nuclear fusion
Explanation: In the solar core, hydrogen nuclei ultimately fuse into helium through thermonuclear processes. A small loss of mass appears as radiant energy, keeping the Sun luminous. Nuclear fission does not dominate the energy budget of the Sun.
Q51. Cobalt-60 is used in which medical application among the options?
[WBCS Mains 2021 exam (held May 2022), Paper IV]
(A) Electricity generation
(B) Nuclear fission fuel
(C) Fusion fuel
(D) Cancer detection or treatment
Answer: (D) Cancer detection or treatment
Explanation: Cobalt-60 emits penetrating gamma radiation and is used in medical radiotherapy and industrial inspection. Its photons can damage tumour-cell DNA when a carefully planned radiation dose is delivered. It does not function as the usual fuel for a reactor.
Q50. Which radiation listed carries the greatest energy per photon?
[WBCS Executive Preliminary Examination (2022)]
(A) Ultraviolet
(B) Gamma rays
(C) X-rays
(D) Infrared
Answer: (B) Gamma rays
Explanation: Gamma rays generally occupy the highest-energy, shortest-wavelength region among the listed electromagnetic bands. Photon energy follows E = hf, so radiation with greater frequency carries more energy per photon and often shows stronger penetrating ability.
Q49. Which of the listed locations contains an atomic power station?
[SSC CGL Tier-I (12 December 2022, Shift 1)]
(A) Hirakud
(B) Naharkatiya
(C) Kakrapar
(D) Tatipaka
Answer: (C) Kakrapar
Explanation: Kakrapar in Gujarat has a nuclear electricity station using fission reactors. Hirakud is associated with hydropower, while Naharkatiya and Tatipaka are associated with petroleum or natural-gas installations rather than nuclear generation.
Q48. If alpha, beta and gamma radiations have the same momentum magnitude, how do their associated wavelengths compare?
[SSC CGL memory-based test (2 December 2022, Shift 1)]
(A) Alpha has the greatest
(B) Beta has the greatest
(C) Gamma has the greatest
(D) All wavelengths are equal
Answer: (D) All wavelengths are equal
Explanation: For equal momentum p, the associated wavelength is λ = h/p. Thus the numerical wavelengths are identical. Alpha and beta are matter particles, whereas gamma radiation consists of photons, but the momentum-wavelength relation still applies.
Q47. Which is the radioactive isotope of hydrogen?
[SSC CPO Tier-I (10 November 2022, Shift 2)]
(A) Xenon
(B) Technetium
(C) Thorium
(D) Tritium
Answer: (D) Tritium
Explanation: Tritium, or hydrogen-3, has one proton and two neutrons. It undergoes beta-minus decay and is used as a tracer and in fusion research. Ordinary protium and stable deuterium do not undergo spontaneous radioactive decay.
Q46. Who collaborated with Ernest Lawrence in developing the cyclotron?
[SSC CPO Tier-I (9 November 2022, Shift 3)]
(A) J. J. Thomson
(B) Ernest Rutherford
(C) M. S. Livingston
(D) Enrico Fermi
Answer: (C) M. S. Livingston
Explanation: Milton Stanley Livingston worked with Ernest O. Lawrence on early cyclotron development. The device accelerates charged particles by combining an oscillating electric field with a magnetic field, enabling experimental studies of atomic nuclei.
Q45. Which was India’s first operating nuclear electricity station?
[RRB Group D (18 August 2022, memory-based)]
(A) Tarapur
(B) Narora
(C) Rajasthan Atomic Power Station
(D) Kalpakkam
Answer: (A) Tarapur
Explanation: Tarapur Atomic Power Station in Maharashtra began commercial nuclear electricity generation in 1969 and is recognised as India’s first nuclear power station. Narora, Rawatbhata and Kalpakkam began operations later.
Q44. Assess these statements:
(1) Radioactivity is a property of atomic nuclei.
(2) A hydrogen bomb relies principally on nuclear fission.
Which is correct?
[UPPCS Preliminary Examination (2021)]
(A) Statement 1 only
(B) Statement 2 only
(C) Both statements
(D) Neither statement
Answer: (A) Statement 1 only
Explanation: Radioactive emissions originate in unstable nuclei, so radioactivity is a nuclear property. A hydrogen bomb is thermonuclear and derives major energy from nuclear fusion, even though fission is generally used to initiate it.
Q43. Which option links the origin of nuclear energy with the physicist who expressed mass–energy equivalence?
[UPSC NDA-II General Ability Test (14 November 2021)]
(A) Nuclear fission — Einstein
(B) Nuclear fission — Rutherford
(C) Nuclear fusion — Bohr
(D) Nuclear fusion — Heisenberg
Answer: (A) Nuclear fission — Einstein
Explanation: The intended pairing is nuclear fission with Einstein’s mass–energy equivalence. Nuclear energy may arise from either fission or fusion, and Einstein’s E = mc² explains how a small mass deficit can yield substantial released energy.
Q42. Regarding fission:
(1) It can describe cell division in some unicellular organisms.
(2) It converts heavy nuclei into smaller nuclei.
(3) It creates heavy nuclei by combining smaller nuclei.
Which are correct?
[UPSC CDS-I General Knowledge (2021)]
(A) 1 only
(B) 2 only
(C) 1 and 2 only
(D) 1 and 3 only
Answer: (C) 1 and 2 only
Explanation: The term fission is used in biology for a form of cell division and in physics for splitting heavy nuclei. Combining light nuclei instead describes nuclear fusion. Consequently, statements one and two apply, while statement three does not.
Q41. What is the SI unit used for radioactive activity?
[RRB NTPC CBT-I (13 March 2021, Shift 2)]
(A) Faraday
(B) Becquerel
(C) Rutherford
(D) Curie
Answer: (B) Becquerel
Explanation: One becquerel represents one nuclear disintegration per second. The curie is an older, much larger non-SI activity unit equal to 3.7 × 10¹⁰ becquerels. Radioactive activity describes decay rate, not energy absorbed by tissue.
Q40. Henri Becquerel discovered which phenomenon?
[RRB NTPC CBT-I (4 February 2021, Shift 2)]
(A) Ultraviolet radiation
(B) Infrared radiation
(C) X-rays
(D) Spontaneous radioactivity
Answer: (D) Spontaneous radioactivity
Explanation: Becquerel observed that uranium salts affected photographic plates even without exposure to light. This established spontaneous radioactivity. Wilhelm Röntgen is associated with the discovery of X-rays, an entirely different historical experiment.
Q39. The mineral carnotite is an important source of which element?
[SSC MTS 2020 exam (held 22 October 2021, Shift 1)]
(A) Copper
(B) Zinc
(C) Uranium
(D) Iron
Answer: (C) Uranium
Explanation: Carnotite is a hydrated potassium uranium vanadate mineral and therefore an ore of uranium, often associated with vanadium. Uranium isotopes underpin nuclear fuel cycles, while the mineral itself is not used directly as reactor fuel.
Q38. Why are some Indian nuclear reactors subject to IAEA safeguards while other reactors are not?
[UPSC Civil Services Preliminary Examination (2020)]
(A) They operate on thorium rather than uranium
(B) They use imported rather than domestically sourced uranium
(C) They are privately rather than publicly operated
(D) They are foreign-owned
Answer: (B) They use imported rather than domestically sourced uranium
Explanation: Under India’s civil nuclear agreements, designated civilian installations using imported fuel are placed under International Atomic Energy Agency safeguards. The distinction reflects fuel-supply and safeguards commitments rather than an intrinsic difference in the science of fission.
Q37. Which assertion about neutrons is false?
[UPSC CDS-II General Knowledge (2020)]
(A) A neutron has almost a proton’s mass
(B) A neutron is electrically neutral
(C) Neutrons occur within atomic nuclei
(D) Neutrons orbit nuclei like electrons
Answer: (D) Neutrons orbit nuclei like electrons
Explanation: Neutrons are nucleons that reside within most atomic nuclei alongside protons. Their electric charge is zero, and their mass is close to a proton’s. Electrons, rather than neutrons, occupy atomic electronic states outside the nucleus.
Q36. What was the weapon codenamed “Little Boy”?
[UPSC CDS General Knowledge (8 November 2020)]
(A) A fission bomb used at Hiroshima
(B) A fusion bomb used at Nagasaki
(C) The first US test device
(D) North Korea’s first test device
Answer: (A) A fission bomb used at Hiroshima
Explanation: Little Boy was the uranium-based fission weapon dropped on Hiroshima on 6 August 1945. It derived its explosive energy from an uncontrolled nuclear chain reaction. The Nagasaki bomb, Fat Man, used a different plutonium fission design.
Q35. Which mineral is associated with fuel extraction for nuclear power stations?
[UPSC NDA-I General Ability Test (2019)]
(A) Bauxite
(B) Quartz
(C) Feldspar
(D) Pitchblende
Answer: (D) Pitchblende
Explanation: Pitchblende, also known as uraninite, is a uranium-rich mineral. Uranium recovered from ores can be processed into nuclear fuel. Bauxite chiefly yields aluminium, while quartz and feldspar are common silicate minerals.
Q34. What is the central operating principle of a commercial nuclear reactor?
[UPSC NDA-I General Ability Test (2019)]
(A) Uncontrolled fusion
(B) Controlled fusion
(C) Uncontrolled fission
(D) Controlled fission
Answer: (D) Controlled fission
Explanation: Commercial nuclear reactors sustain controlled fission chain reactions. Neutrons split fissile nuclei, releasing heat and further neutrons, while control systems regulate reactivity. Fusion remains primarily a research technology rather than the standard basis of commercial reactors.
Q33. About joining the Nuclear Suppliers Group, consider:
1. Membership supports access to nuclear technologies.
2. It automatically confers NPT membership.
Which is correct?
[UPSC Civil Services Preliminary Examination (2018)]
(A) 1 only
(B) 2 only
(C) Both
(D) Neither
Answer: (A) 1 only
Explanation: The Nuclear Suppliers Group coordinates controls on nuclear-related exports and may facilitate legitimate technology trade among participating states. NSG participation does not automatically make a country a party to the separate Nuclear Non-Proliferation Treaty.
Q32. India’s ratification of the IAEA Additional Protocol chiefly relates to which consequence?
[UPSC Civil Services Preliminary Examination (2018)]
(A) Certain civilian reactors becoming subject to IAEA safeguards
(B) All military nuclear sites being opened automatically
(C) Automatic NSG membership
(D) Guaranteed uranium imports from any country
Answer: (A) Certain civilian reactors becoming subject to IAEA safeguards
Explanation: The Additional Protocol expands information and access arrangements associated with safeguards for designated civilian nuclear facilities. It does not automatically place military installations under safeguards, create NSG membership or confer unrestricted rights to purchase nuclear fuel.
Q31. Which fallout isotopes may enter humans through food chains and cause physiological harm?
[UPSC CDS-II General Knowledge (2017)]
(A) Strontium-90 only
(B) Iodine-131 only
(C) Caesium-137 only
(D) All three listed isotopes
Answer: (D) All three listed isotopes
Explanation: Radioactive strontium-90 can accumulate in bones, iodine-131 concentrates in the thyroid, and caesium-137 behaves chemically somewhat like potassium. These radionuclides can enter food and water after contamination and expose internal organs to ionising radiation.
Q30. A reactor and a nuclear bomb both involve a chain reaction. Which statement correctly distinguishes them?
[UPSC CDS-II General Knowledge (2017)]
(A) Reactors have no chain reaction
(B) Reactor reactions are controlled, weapon reactions are uncontrolled
(C) Only bombs involve any criticality
(D) Reactors always use bomb-type moderators
Answer: (B) Reactor reactions are controlled, weapon reactions are uncontrolled
Explanation: A functioning fission reactor controls neutron multiplication to maintain useful steady heat output. A nuclear fission weapon produces an extremely rapid, uncontrolled energy release. Both rely on chain reactions, but their reaction rates and engineering purposes differ.
Q29. Consider:
(1) Nuclear Security Summits were convened directly under the UN.
(2) The International Panel on Fissile Materials is part of IAEA.
Which is right?
[UPSC Civil Services Preliminary Examination (2017)]
(A) 1 only
(B) 2 only
(C) Both
(D) Neither
Answer: (D) Neither
Explanation: Nuclear Security Summits were intergovernmental initiatives rather than meetings organised under the UN framework. The International Panel on Fissile Materials is an independent expert group, not an organ of the International Atomic Energy Agency.
Q28. What would be India’s principal prospective benefit if the ITER fusion experiment proves successful?
[UPSC Civil Services Preliminary Examination (2016)]
(A) Direct conversion of thorium into reactor electricity
(B) Satellite navigation capability
(C) Improved efficiency of existing fission plants alone
(D) Knowledge enabling future fusion power plants
Answer: (D) Knowledge enabling future fusion power plants
Explanation: ITER investigates magnetic confinement of very hot plasma to demonstrate large-scale fusion technology. Its success could provide knowledge and experience essential for future fusion electricity generation, rather than directly modifying the operation of conventional fission reactors.
Q27. Which claim is NOT characteristic of nuclear fission?
[Uttarakhand PCS Preliminary Examination (2016)]
(A) It can be induced by neutrons
(B) It is the main process producing energy in stars
(C) It is used in ordinary nuclear reactors
(D) It can release vast energy in fission weapons
Answer: (B) It is the main process producing energy in stars
Explanation: Stars such as the Sun produce energy mainly through fusion of light nuclei, not fission of heavy nuclei. Fission involves splitting a heavy nucleus and is harnessed in commercial reactors and fission weapons.
Q26. About proposed fusion reactors:
(i) They split heavy nuclei.
(ii) They commonly employ tokamak designs.
(iii) They require very high temperatures.
Select the correct statements.
[UPPSC RO/ARO Preliminary Examination (2016)]
(A) i and iii only
(B) i and ii only
(C) ii and iii only
(D) All three
Answer: (C) ii and iii only
Explanation: Fusion involves combining light nuclei, so statement one incorrectly describes fission. Tokamaks use magnetic fields to confine plasma, and the reacting fuel must be heated to extreme temperatures to overcome the electrostatic repulsion between nuclei.
Q25. During gamma decay of a nucleus, which nuclear quantities change?
[UPSC CDS-II General Knowledge (2016)]
(A) Mass number only
(B) Atomic number only
(C) Both change
(D) Neither atomic nor mass number changes
Answer: (D) Neither atomic nor mass number changes
Explanation: Gamma emission releases excess nuclear excitation energy as a high-energy photon. Because no proton or neutron is added or removed, both atomic number and mass number remain unchanged. The nucleus merely drops to a lower energy state.
Q24. Among China, France, India, Israel and Pakistan, which are nuclear-weapon states recognised under the NPT?
[UPSC Civil Services Preliminary Examination (2015)]
(A) China and France only
(B) China, India, Israel and Pakistan
(C) France, Israel and Pakistan
(D) All five
Answer: (A) China and France only
Explanation: The Nuclear Non-Proliferation Treaty recognises as nuclear-weapon states countries that detonated a nuclear explosive before 1 January 1967: China, France, Russia, the United Kingdom and the United States. India, Israel and Pakistan are not recognised in that category.
Q23. Graphite serves which purpose inside certain nuclear reactors?
[UPPSC Main Examination (2015)]
(A) Fissile fuel
(B) Mechanical lubricant
(C) Neutron moderator
(D) Radiation detector
Answer: (C) Neutron moderator
Explanation: Graphite can slow fast neutrons through elastic collisions without absorbing too many of them. In thermal reactors, this moderation can improve the probability that fissile nuclei capture neutrons and undergo fission, helping sustain the chain reaction.
Q22. Which substance is NOT normally treated as a nuclear fuel?
[Chhattisgarh PCS Preliminary Examination (2014)]
(A) Uranium
(B) Thorium
(C) Plutonium
(D) Lead
Answer: (D) Lead
Explanation: Uranium and plutonium contain isotopes used directly as fissile reactor fuels; thorium is fertile and can breed uranium-233. Ordinary lead is not used as a fissile nuclear fuel, although lead-based materials may serve as coolant or shielding.
Q21. Which metal was the correct choice in a question about material used in nuclear-bomb manufacture?
[MPPSC Preliminary Examination (2014)]
(A) Zirconium
(B) Uranium
(C) Molybdenum
(D) Vanadium
Answer: (B) Uranium
Explanation: The examination identified uranium, whose isotope uranium-235 is capable of sustaining a rapid fission chain reaction under suitable conditions. Zirconium is important in reactor cladding, but is not the fissile material indicated by the question.
Q20. Which element among these is not used as nuclear fuel?
[UPPCS Main Examination (2014)]
(A) Uranium
(B) Thorium
(C) Calcium
(D) Plutonium
Answer: (C) Calcium
Explanation: Uranium and plutonium have important fission-related isotopes, while thorium can be converted into fissile uranium-233. Calcium lacks a practical role as a nuclear fuel and is not used for sustaining power-producing fission reactions.
Q19. Which element is the stable end product of major natural uranium radioactive decay chains?
[Chhattisgarh PCS Preliminary Examination (2013)]
(A) Lead
(B) Radium
(C) Thorium
(D) Plutonium
Answer: (A) Lead
Explanation: Uranium-238 undergoes a sequence of alpha and beta decays leading ultimately to stable lead-206. Uranium-235 similarly decays through a series ending in lead-207. Intermediates such as radium remain radioactive rather than being final stable products.
Q18. Concerning thorium fuel:
(1) It is more abundant than uranium.
(2) It may deliver more useful energy per mined mass through appropriate cycles.
(3) It can reduce some long-lived waste.
Which are correct?
[UPSC Civil Services Preliminary Examination (2012)]
(A) 1 only
(B) 2 and 3 only
(C) 1 and 3 only
(D) 1, 2 and 3
Answer: (D) 1, 2 and 3
Explanation: Thorium is relatively abundant and can be bred into uranium-233 in suitable reactors. The intended UPSC answer accepted all three potential advantages. Actual performance and waste characteristics depend strongly on reactor design and fuel-cycle technology.
Q17. Which uranium isotope is conventionally used as fissile fuel for nuclear-electricity production?
[Uttarakhand PCS Preliminary Examination (2012)]
(A) Uranium-233
(B) Uranium-234
(C) Uranium-235
(D) Uranium-239
Answer: (C) Uranium-235
Explanation: Uranium-235 is a naturally occurring fissile isotope capable of sustaining thermal-neutron-induced fission. It constitutes less than one percent of natural uranium. Certain reactor types enrich its proportion, while pressurised heavy-water reactors can use natural uranium.
Q16. Heavy water used within many nuclear reactors principally has what function?
[UPSC Civil Services Preliminary Examination (2011)]
(A) To reduce neutron speeds
(B) To speed up neutrons
(C) Only to cool the turbine
(D) To stop fission completely
Answer: (A) To reduce neutron speeds
Explanation: Heavy water, D₂O, can act as a neutron moderator. By slowing fast neutrons without absorbing many, it makes thermal fission more likely in appropriate fuels. It may also serve as coolant in certain reactor designs.
Q15. Which material listed is used to moderate neutrons inside a nuclear reactor?
[UPPCS Main Examination (2011)]
(A) Thorium
(B) Heavy water
(C) Radium
(D) Ordinary water
Answer: (B) Heavy water
Explanation: Heavy water is a widely used neutron moderator because deuterium transfers kinetic energy from fast neutrons while capturing relatively few. Ordinary water also moderates neutrons in many other reactor types, so the original question’s options can be ambiguous.
Q14. A hydrogen bomb releases its main energy through which reaction?
[UPPCS Preliminary Examination (2010)]
(A) Controlled fusion
(B) Uncontrolled fusion
(C) Controlled fission only
(D) Uncontrolled fission only
Answer: (B) Uncontrolled fusion
Explanation: Thermonuclear explosive energy arises from rapid fusion of light hydrogen isotopes, commonly deuterium and tritium or related fuel systems. Because the release is deliberately explosive, it is an uncontrolled reaction unlike experimental magnetic-confinement fusion.
Q13. What fluid was identified as coolant in the Fast Breeder Test Reactor at Kalpakkam?
[UPPCS Main Examination (2010)]
(A) Carbon dioxide
(B) Heavy water
(C) Seawater
(D) Liquid sodium
Answer: (D) Liquid sodium
Explanation: Liquid sodium is used as coolant in many fast breeder reactors because it transfers heat effectively without significantly slowing neutrons. The Kalpakkam Fast Breeder Test Reactor operates with a fast-neutron spectrum rather than heavy-water moderation.
Q12. What does the term “enriched uranium” mean?
[UPPCS Preliminary Examination (2009)]
(A) Uranium shaped into rods
(B) Uranium with an artificially increased proportion of uranium-235
(C) A mixture of uranium and thorium
(D) Chromium-coated uranium
Answer: (B) Uranium with an artificially increased proportion of uranium-235
Explanation: Natural uranium has only about 0.7% uranium-235. Enrichment increases the fraction of this fissile isotope by separating isotopes, permitting its use in many kinds of nuclear reactors. Enrichment is not simply coating fuel rods.
Q11. A breeder reactor is distinguished by its ability to do what?
[UPPCS Main Examination (2009)]
(A) Operate without nuclear fuel
(B) Use only heavy water
(C) Produce more fissile material than it consumes
(D) Operate entirely from solar cells
Answer: (C) Produce more fissile material than it consumes
Explanation: A breeder reactor converts fertile isotopes, such as uranium-238, into fissile products while generating energy. With suitable neutron economy, it can create more fissile material than it burns, extending available nuclear-fuel resources.
Q10. ITER, the international fusion-energy project, is located in which region?
[UPSC Civil Services Preliminary Examination (2008)]
(A) Northern Spain
(B) Southern France
(C) Eastern Germany
(D) Southern Italy
Answer: (B) Southern France
Explanation: The International Thermonuclear Experimental Reactor project is at Cadarache in southern France. ITER is designed to test large-scale magnetic confinement of fusion plasma, a potential route to future electricity generation if engineering challenges are solved.
Q9. Which country was first to conclude a civil nuclear cooperation agreement with India after the 2008 NSG waiver?
[MPPSC Preliminary Examination (2008)]
(A) United States
(B) Italy
(C) Russia
(D) France
Answer: (D) France
Explanation: France concluded a civil nuclear cooperation agreement with India after the Nuclear Suppliers Group granted India a waiver in 2008. The question concerns civilian nuclear trade, international safeguards and access to peaceful nuclear technology.
Q8. A radioactive substance has a half-life of ten days. How much will have decayed after twenty days?
[RAS/RTS Preliminary Examination (2007)]
(A) One-half
(B) One-quarter
(C) Three-quarters
(D) One-eighth
Answer: (C) Three-quarters
Explanation: Twenty days spans two half-lives. The remaining fraction is (1/2)² = 1/4, meaning 3/4 of the original nuclei have decayed. Half-life describes a statistical exponential process rather than an exact lifetime for each nucleus.
Q7. Which fuel type was associated with the Fast Breeder Test Reactor at Kalpakkam?
[Uttarakhand PCS Preliminary Examination (2006)]
(A) Enriched uranium alone
(B) Thorium alone
(C) Plutonium-bearing fuel
(D) Tungsten
Answer: (C) Plutonium-bearing fuel
Explanation: The Kalpakkam Fast Breeder Test Reactor has used mixed plutonium–uranium carbide fuel. Plutonium provides fissile material, while uranium supports breeding and the fast-neutron fuel cycle. Tungsten is not its nuclear fuel.
Q6. Which listed metal is employed as an energy source in nuclear-electricity production?
[47th BPSC Preliminary Examination (2005)]
(A) Uranium
(B) Iron
(C) Copper
(D) Aluminium
Answer: (A) Uranium
Explanation: Uranium is used as fuel for fission-based nuclear electricity generation. Its fissile uranium-235 nuclei release heat when split by neutrons. Iron, copper and aluminium are useful industrial metals but are not conventional reactor fuels.
Q5. What connects the facilities Dhruva, Purnima and CIRUS?
[UPPCS Main Examination (2004)]
(A) They are Indian research reactors
(B) They are stars
(C) They are books
(D) They are hydropower dams
Answer: (A) They are Indian research reactors
Explanation: Dhruva, Purnima and CIRUS are names associated with Indian nuclear research reactors. Research reactors provide neutron fluxes for experiments, isotope production and materials studies, rather than necessarily being used for grid-scale electricity production.
Q4. In which state is the Indira Gandhi Centre for Atomic Research located?
[UPPCS Main Examination (2004)]
(A) Maharashtra
(B) Tamil Nadu
(C) Uttar Pradesh
(D) Karnataka
Answer: (B) Tamil Nadu
Explanation: The Indira Gandhi Centre for Atomic Research is situated at Kalpakkam in Tamil Nadu. It is associated with fast-reactor technology and advanced nuclear-fuel-cycle studies, playing a distinct research role alongside India’s commercial power plants.
Q3. Which pair names sites that both house nuclear generating stations?
[UPPCS Main Examination (2004)]
(A) Ghatshila and Nangal
(B) Narora and Kalpakkam
(C) Nangal and Ghatshila only
(D) Ghatshila and Kalpakkam only
Answer: (B) Narora and Kalpakkam
Explanation: Narora in Uttar Pradesh and Kalpakkam in Tamil Nadu have nuclear generating facilities. Nangal is principally associated with hydropower infrastructure. Identifying these sites helps distinguish nuclear electricity from other forms of generation.
Q2. Which mineral or element listed is NOT characteristically associated with nuclear-power raw materials?
[Chhattisgarh PCS Preliminary Examination (2003)]
(A) Monazite
(B) Thorium
(C) Beryllium
(D) Chromium
Answer: (D) Chromium
Explanation: Monazite is a source of thorium; thorium has a role in advanced nuclear fuel cycles. Beryllium compounds can be relevant in reactor technology. Chromium is not normally singled out as a nuclear-power fuel resource.
Q1. For which facility is Kalpakkam particularly famous?
[UP Lower Subordinate Preliminary Examination (2002)]
(A) A nuclear power plant
(B) A missile-test range
(C) A rocket-launch pad
(D) A satellite tracking site
Answer: (A) A nuclear power plant
Explanation: Kalpakkam on the Tamil Nadu coast hosts the Madras Atomic Power Station and important nuclear research infrastructure. It is a major centre for India’s nuclear energy programme rather than a missile or satellite launch complex.