$C-14$ is used in carbon dating of dead objects because

The decay constant of a radioactive element is $3 \times 10^{-6} \ min^{-1}$. Its half-life is

The half-life of a radioactive element is $6 \ months$. The time taken to reduce its original concentration to its $1/16$ value is ....... $years$.

The decay of a radioactive element follows first-order kinetics. As a result:

$2 \text{ g}$ of a radioactive sample having a half-life of $15$ days was synthesized on $1^{st}$ Jan $2009$. The amount of the sample left behind on $1^{st}$ March $2009$ (including both the days) is: (in $\text{ g}$)

The half-life period of ${}_{53}I^{125}$ is $60$ days. The radioactivity after $180$ days will be (in $\%$)