AIIMS2019Physics-Nuclear Physics

AIIMS 2019 Physics Nuclear Reactors Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 12

Assertion: Heavy water is used to slow down neutron in nuclear reactor Reason: It does not react with slow speed neutron and mass of deuterium is comparable to the neutron

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

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

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Correct Answer

Option C

Detailed Explanation

The assertion is true because heavy water (D₂O) is indeed used in nuclear reactors to slow down neutrons, enhancing the likelihood of fission reactions. However, the reason is false; while deuterium (the hydrogen isotope in heavy water) has a mass comparable to that of a neutron, it does interact with slow neutrons, primarily through elastic scattering, which is essential for moderation. Option A is incorrect because the reason does not correctly explain the assertion, while option B is incorrect as the reason is not true. Option D is incorrect since the assertion is valid.

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