Radioacitive nuclei $A$ and $B$ disintegrate into $C$ with half lives $T$ and $2T$. At $t = 0$, pumber of nuclei of each $A$ and $B$ is $x$. The number of nuclei of $C$ when rate of disintegration of $A$ and $B$ are equal is
$1.5x$
$125x$
$x$
$1.75x$
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
Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed and when half of the nuclei have decayed is given as:
(where $\lambda$ is the decay constant)
A nucleus has a half-life of $30\; min$. At $3 \;PM$ its decay rate was measured as $120000 \,cps$. the decay rate ........... $\,cps$ at $5 \,PM$ ?
A radioactive sample has an average life of $30\, {ms}$ and is decaying. A capacitor of capacitance $200\, \mu\, {F}$ is first charged and later connected with resistor $^{\prime}{R}^{\prime}$. If the ratio of charge on capacitor to the activity of radioactive sample is fixed with respect to time then the value of $^{\prime}R^{\prime}$ should be $....\,\Omega$
Radioactivity is