Assertion:Heavy water preffered over ordinary water as a moderator in reactors.
Reason:Heavy water,used for slowing down the neurons,has lesser absorption probability of neutrons than ordinary water.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are truw but reason is not correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

A

Explanation

A bombarding particle gives up most energy when it makes an elastic collision with a particle of similar mass.For neutrons,hydrogen atoms would be most effective but unforunately absorption occurs.However,deuterium (Heavy water)and carbon (as graphite)are both suitable in which less absorption occurs therefore they are used as moderators.