Let `T` be the mean life of a radioactive sample. `75%` of the active nuclei present in th sample initially will deacy in time

Options

A. 2T
B. 1/2(ln 2)T
C. 4T
D. 2(ln 2)T

Answer

D

Explanation

`T_a=T`
`(1/2)^2=25/100N_0=N_0(1/2) t/T_n`
`2=t/(T_n) " " {T_a=1/lambda " " & " " T_n="ln2"/lambda}`
`t=2T_n =(2ln)/lambda=` 2Tln2