Mean life of a radioactive sample is $100$ seconds. Then its half life (in minutes) is
$0.693$
$1$
$10^{-4}$
$1.155$
The initial activity of a certain radioactive isotope was measured as $16000\ counts\ min^{-1}$. Given that the only activity measured was due to this isotope and that its activity after $12\, h$ was $2000\ counts\ min^{-1}$, its half-life, in hours, is nearest to
A radioactive substance is being produced at a constant rate of $10\, nuclei/s.$ The decay constant of the substance is $1/2\, sec^{-1}.$ After what time the number of radioactive nuclei will become $10$ $?$ Initially there are no nuclei present. Assume decay law holds for the sample.
The half life of a radioactive substance against $\alpha - $ decay is $1.2 \times 10^7\, s$. What is the decay rate for $4.0 \times 10^{15}$ atoms of the substance
Certain radio-active substance reduces to $25\%$ of its value in $16$ days. Its half-life is ........ $days$
The particle that possesses half integral spin as