At $t = 0$, number of active nuclei in a sample is $N_0$. How much no. of nuclei will decay in time between its first mean life and second half life?
$\frac{{{N_0}}}{e}$
$\frac{{{N_0}}}{e} - \frac{{{N_0}}}{4}$
$\frac{{{N_0}}}{2} - \frac{{{N_0}}}{e}$
$\frac{{{N_0}}}{4}$
The fraction $f$ of radioactive material that has decayed in time $t$, varies with time $t$. The correct variation is given by the curve
Half life period of a sample is $15$ years. How long will it take to decay $96.875\%$ of sample .......... $years$
A radio-active material is reduced to $1 / 8$ of its original amount in $3$ days. If $8 \times 10^{-3}\,kg$ of the material is left after $5$ days. The initial amount of the material is $.......\,g$
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 $..............$
Ther percentage of ${ }^{235} U$ presently on earth is $0.72$ and the rest $(99.28 \%)$ may be taken to be ${ }^{233} U$. Assume that all uranium on earth was produced in a supernova explosion long ago with the initial ratio ${ }^{235} U /^{335} U =2.0$. How long ago did the supernova event occur? (Take the half-lives of ${ }^{235} U$ and ${ }^{238} U$ to be $7.1 \times 10^5$ years and $4.5 \times 10^{9}$ years respectively)