Question:
A radioactive nucleus $\mathrm{A}$ with a half life $\mathrm{T}$, decays into a nucleus $\mathrm{B}$. At $\mathrm{t}=0$, there is no nucleus B. At sometime $t$, the ratio of the number of $B$ to that of $A$ is $0.3$. Then, $t$ is given by :
Correct Option: , 4
Solution:
