A radioactive nuclide is produced at the constant rate of $n$ per second (say, by bombarding a target with neutrons). The expected number $N$ of nuclei in existence $t\, seconds$ after the number is $N_0$ is given by Where $\lambda $ is the decay constant of the sample
$N = N{ _0}{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + {N_0}{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + \left( {{N_0} - \frac{n}{\lambda }} \right)\,{e^{ - \lambda t}}$
$N = \frac{n}{\lambda } + \left( {{N_0} + \frac{n}{\lambda }} \right)\,{e^{ - \lambda t}}$
The activity of a sample is $64 × 10^{-5}\, Ci.$ Its half-life is $3\, days$. The activity will become $5 × 10^{-6}\, Ci$ after .........$days$
If half-life of a substance is $3.8\, days$ and its quantity is $10.38\, gm$. Then substance quantity remaining left after $19\, days$ will be ........$gm$
At any instant, two elements $X _1$ and $X _2$ have same number of radioactive atoms. If the decay constant of $X _1$ and $X _2$ are $10 \lambda$ and $\lambda$ respectively. then the time when the ratio of their atoms becomes $\frac{1}{e}$ respectively will be
The nuclear activity of a radioactive element becomes $\left(\frac{1}{8}\right)^{\text {th }}$ of its initial value in $30\, years.$ The half-life of radioactive element is $....\,years.$
Half life of a radioactive substance is $T$. The time taken for all the nuclei to disintegrate will be