A radioactive substance has a half-life of `1` year. The fraction of this material, that would remain after `5` years will be.

Options

A. `(1)/(32)`
B. `(1)/(5)`
C. `(1)/(2)`
D. `(4)/(5)`

Answer

A

Explanation

(a) Number of half lives `n = (5)/(1) = 5`
Now `(N)/(N_0) = ((1)/(2))^n rArr (N)/(N_0) = ((1)/(2))^5 = (1)/(32)`.