Which law explains why rockets work in outer space?

Last Updated: 25 Jun 2026

The most useful approach is to identify the physical quantity, phenomenon, law, or device named in the stem and connect it with its standard definition. Here, the relevant answer is “Newton's Third Law.” A sound solution relies on the governing concept rather than a memorised option letter, because option order may change in another paper. Physics explains measurable natural events through quantities, units, observations, mathematical relations, and experimentally verified laws. The distractors in this question—Newton's First Law, Newton's Second Law, Archimedes' Principle—do not satisfy the exact condition stated. The final selection must agree with the explanation and marked answer: Newton's Third Law.

ANewton's First Law

BNewton's Second Law

CNewton's Third Law

DArchimedes' Principle

Correct Answer: Newton's Third LawYour Answer: C

Explanation

law, relation, or working principle involved. — the scientifically appropriate response is Newton's Third Law. Option-wise review: Newton's Third Law is correct under the condition given in the stem. Newton's First Law is incorrect because it describes a different quantity or phenomenon and does not meet the stated condition. Newton's Second Law is also incorrect; although it may be a valid physics term, its definition or application is not the one asked here. Archimedes' Principle is incorrect because it fails the governing relation or characteristic relevant to this case. Therefore, option C, Newton's Third Law, is factually and logically consistent with the question. Rockets work on Newton's Third Law - gases expelled backward propel the rocket forward.

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 Newton's Third Law.
Use dimensional consistency as a quick check for formulas. Both sides of a valid physical equation must have the same dimensions. Units can eliminate distractors quickly, although a dimensionally correct option must still satisfy the actual law.
Eliminate Newton's First Law, Newton's Second Law, Archimedes' Principle here because none fulfils the exact requirement of the stem. The final answer and correct-index field must point to option C.
Exam memory point: connect Newton's Third Law directly with the key wording of the question, then verify it once against the relevant definition or formula before marking the answer.Works even in vacuum

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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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