A radioactive substance has `t_(1//2)` 60 minutes. After 3 hrs, what percentage of radioactive substance will remain ?

Options

A. 0.5
B. 1.75
C. 0.25
D. 0.125

Answer

D

Explanation

No. of half lives in 3 hrs =3
`:.C_(n)=(1)/(2^(n))=(1)/(2^(3))=(1)/(8)`
`:.` Amount left =12.5%