Question:
The half life of a radioactive substance is 20 minutes. The approximate time interval $\left(t_{2}-t_{1}\right)$ between the time $t_{2}$ when $\frac{2}{3}$ of it has decayed and time $t_{1}$ when $\frac{1}{3}$ of it had decayed is :-
Correct Option: 1
Solution:
