At a given instant there are `25%` undecayed ratio-activity nuclei in sample. After `10` second, the number of undecyed nuclei reduces to `12.5%`. Calculate
(a) mean-life of the nuclei and
(a) the time in which the number undecayed nuclei will further reduce to `6.25%` of the reduced number.

Explanation

(a) Half-like `T_(1//2) = 10 sec`
Meanlife `bar(T) = 1.44T_(1//2) = 1.44 xx 10 = 1.44 sec`
(b) `(N_(0))/(4) overset(T_(1//2))rarr(N_(0))/(8)overset(T_(1//2))rarr(N_(0))/(16)`
`t = T_(1//2) = 10 sec`