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

`(1)/(16) = ((1)/(2))^((t)/(T_(1//2))) rArr ((1)/(2))^(4) = ((1)/(2))^((120)/(T_(1//2)))`
`rArr 4= (120)/(T_(1//2)) rArr T_(1//2)= 30` days