A radioactive nucleus decays by two different process. The half life of the first process is $5$ minutes and that of the second process is $30\,s$. The effective half-life of the nucleus is calculated to be $\frac{\alpha}{11}\,s$. The value of $\alpha$ is $..............$
$301$
$302$
$300$
$303$
The half life of a radioactive isotope $'X'$ is $20$ years, It decays to another element $'Y'$ which is stable. The two elements $'X'$ and $'Y'$ were found to be in the ratio $1:7$ in a simple of a given rock . The age of the rock is estimated to be............$years$
Activity of a radioactive sample decreases to $(1/3)^{rd}$ of its original value in $3\, days$. Then, in $9\, days$ its activity will become
Define the average life of a radioactive substance.
The half life of radioactive Radon is $3.8\, days$. The time at the end of which $1/20^{th}$ of the Radon sample will remain undecayed is ............ $days$ (Given $log_{10}e = 0.4343$ )
Radioactive nuclei $P$ and $Q$ disintegrate into $R$ with half lives 1 month and 2 months respectively. At time $t=$ 0 , number of nuclei of each $P$ and $Q$ is $x$. Time at which rate of disintegration of $P$ and $Q$ are equal, number of nuclei of $R$ is ........ $x$