Calculate the time (in $minutes$) interval between $33 \,\%$ decay and $67\, \%$ decay if half-life of a substance is $20\, minutes.$
$60$
$20$
$40$
$13$
A radioactive nucleus decays by two different processes. The half life for the first process is $10\, s$ and that for the second is $100 s$. the effective half life of the nucleus is close to$.....sec$
The activity of a sample reduces from $A_0$ to ${A_0} / \sqrt{3}$ in one hour. The activity after $3$ hours more will be
The half-life of radon is $3.8\, days$. Three forth of a radon sample decay in ............$days$
The plot of the number $(N)$ of decayed atoms versus activity $(A)$ of a radioactive substance is
The half-life of a radioactive substance is $20\, min$. 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 (in $min$)