A radioactive material has an initial amount `16 gm` After `120` days it reduces to `1 gm`. Then the half-life of radioactive material is

Options

A. 60 days
B. 30 days
C. 40 days
D. 240 days

Answer

B

Explanation

(b) `(N)/(N_0) = ((1)/(2))^n rArr ((1)/(16)) = ((1)/(16)) = ((1)/(2))^n rArr n = 4`
also `n = (t)/(T_(1//2)) rArr T_(1//2) = (120)/(4) = 30 days`.