What is the working principle of a nuclear reactor?

Last Updated: 25 Jun 2026

What is the working principle of a nuclear reactor? Here, the relevant answer is “Nuclear fission.” A sound solution relies on the governing concept rather than a memorised option letter, because option order may change in another paper. The distractors in this question—Nuclear fusion, Radioactive decay, Thermonuclear reaction—do not satisfy the exact condition stated. The final selection must agree with the explanation and marked answer: Nuclear fission.

ANuclear fusion

BNuclear fission

CRadioactive decay

DThermonuclear reaction

Correct Answer: Nuclear fissionYour Answer: B

Explanation

elation, or working principle involved. — the scientifically appropriate response is Nuclear fission. Option-wise review: Nuclear fission is correct under the condition given in the stem. Nuclear fusion is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Radioactive decay is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Thermonuclear reaction is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option B, Nuclear fission, is factually and logically consistent with the question. A nuclear reactor works on the principle of controlled nuclear fission of U-235 or Pu-239.

Important Notes

Read the complete stem before looking at the options. Identify whether the demand is a definition, unit, formula, direction, cause, effect, image characteristic, or device principle. In this record, the confirmed answer is Nuclear fission.
Eliminate Nuclear fusion, Radioactive decay, Thermonuclear reaction here because none fulfils the exact requirement of the stem. The final answer and correct-index field must point to option B.
Exam memory point: connect Nuclear fission directly with the key wording of the question, then verify it once against the relevant definition or formula before marking the answer.Moderator slows neutrons

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FAQ

SSC CGL Physics FAQs

Common questions and clear answers for this topic.

How many physics questions usually appear in the SSC CGL exam?

Physics typically makes up a small portion of the General Science questions, usually focused on concepts rather than numerical problems.

Which physics topics are most important for SSC CGL?

Basic mechanics, heat, sound and light, and electricity and magnetism are the areas that come up most consistently across previous papers.

Do I need to solve numerical problems for SSC CGL physics?

Rarely. Most questions are conceptual and test everyday understanding rather than calculation skills.

Is NCERT physics enough for SSC CGL preparation?

NCERT textbooks from classes 9 and 10 build a strong enough conceptual base for most of what SSC CGL asks.

How can I make physics concepts easier to remember for SSC CGL?

Connecting concepts to everyday observations, like why a thermos keeps tea warm, makes them far easier to recall than memorizing definitions.

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