If half-life of a radioactive atom is $2.3\, days$, then its decay constant would be

A piece of wood from a recently cut tree shows $20\,decays$ per minute. A wooden piece of same size placed in a museum ( obtained from a tree cut many years back) shows $2\,decays$ per minute. If half life of $C^{14}$ is $5730\, years$, then age of the wooden piece placed in the museum is approximately ........... $years$

$3.8$ days is the half-life period of a sample. After how many days, the sample will become $\frac{{1}}{{8}} \, th$ of the original substance

The half life of a radioactive sample undergoing $\alpha$ - decay is $1.4 \times 10^{17}$ s. If the number of nuclei in the sample is $2.0 \times 10^{21}$, the activity of the sample is nearly

In a sample of radioactive material, what percentage of the initial number of active nuclei will decay during one mean life .......... $\%$

The radioactive sources $A$ and $B$ have half lives of $2\ hr$ and $4\ hr$  espectively, initially contain the same number of radioactive atoms. At the end of $2\  hours$, their rates of distintegration are in the ratio