363794
Assertion : It is desirable to slow down fast moving neutrons to sustain controlled chain reactions. Reason : Slow moving neutrons efficiently collide with \(U^{235}\).
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
Explanation:
Slow neutrons are essential to keep \(K\)-value of reactor to be unity. So correct option is (1).