A radioactive sample has ${N_0}$ active atoms at $t = 0$. If the rate of disintegration at any time is $R$ and the number of atoms is $N$, then the ratio $ R/N$ varies with time as
Sometimes a radioactive nucleus decays into a nucleus which itself is radioactive. An example is
$\mathop {^{38}S}\limits_{sulpher} \xrightarrow[{ - 2.48\,h}]{{half\,year}}\mathop {^{38}Cl}\limits_{chloride} \xrightarrow[{ - 0.62\,h}]{{half\,year}}\mathop {^{38}Ar}\limits_{Argon} $
Assume that we start with $1000$ $^{38}S$ nuclei at time $t = 0$. The number of $^{38} Cl$ is of count zero at $ t=0$ an will again be zero at $t = \infty $. At what value of $t,$ would the number of counts be a maximum ?
Activities of three radioactive substances $A , B$ and $C$ are represented by the curves $A, B$ and $C,$ in the figure. Then their half-lives $T _{\frac{1}{2}}( A ): T _{\frac{1}{2}}( B ): T _{\frac{1}{2}}( C )$ are in the ratio
Activity of a radioactive substance is $R_1$ at time $t_1$ and $R_2$ at time $t_2(t_2 > t_1).$ Then the ratio $\frac{R_2}{R_1}$ is :
The plot of the number $(N)$ of decayed atoms versus activity $(A)$ of a radioactive substance is
The mean life time of a radionuclide, if its activity decrease by $4\%$ for every $1h$ , would be .......... $h$ [product is non-radioactive i.e. stable]