Deuterium as a Moderator – Rankers Physics

Nucleus: Practice Problem & Solution

Assertion (A): Deuterium is a good moderator of fast neutrons. Reason (R): Fast neutrons transfer 90% of their kinetic energy to the nuclei of the moderator in an elastic collision.  
Both (A) & (R) are true and the (R) is the correct explanation of the (A)
Both (A) & (R) are true but the (R) is not the correct explanation of the (A)
(A) is true but (R) is false
Both (A) and (R) are false

Solution Explained:

To solve this problem, we apply the core principles of Nucleus. Understanding the underlying formula is key to arriving at the correct answer below:

Assertion (A) is true. Deuterium's mass is close to a neutron's, making it efficient for moderation. Reason (R) is true; in elastic collision with deuterium, neutrons lose about 89% of their kinetic energy. (R) is the correct explanation for (A).

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