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Physics · 2026 · 1 mark
CBSE 2026 · Region 1 · Set 1 · Q15
Reason (A): The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R): Energy is absorbed when the nucleons…
Reason (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons.
Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.
Official answer
(C)
Assertion (A) is true, but Reason (R) is false.
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CBSE Class 12 Physics past-paper question from the 2026 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.