AIIMS2019Physics-Nuclear Physics

AIIMS 2019 Physics Nuclear Fission Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 12

In U₂₃₅ fission reaction neutrons are required to be slowed down because the probability of capture of slow moving neutrons is high for U₂₃₅.

A

Both assertion and reason are true and reason is the correct explanation of assertion.

B

Both assertion and reason are true but reason is not the correct explanation of assertion.

C

Assertion is true but reason is false.

D

Both assertion and reason are false.

Correct Answer

Option B

Detailed Explanation

Option B is correct because both the assertion and reason are true: U-235 fission reactions indeed require slow (thermal) neutrons for a higher probability of fission, as these neutrons are more easily captured by U-235 nuclei. However, the reason provided does not explain the assertion adequately; while it states that slow neutrons have a high capture probability, it does not clarify that this is essential for sustaining a chain reaction in nuclear reactors.

Option A is incorrect because, although both statements are true, the reason does not correctly explain the assertion. Option C is wrong because both the assertion and reason are true. Option D is incorrect as both statements are factual and relevant to nuclear fission processes.

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