$A$ wood piece is $11460$ years old. What is the fraction of $^{14}C$ activity left in the piece? (Half-life period of $^{14}C$ is $5730$ years)

If $8.0 \ g$ of a radioactive isotope has a half-life of $10 \ hrs$. The half-life of $2.0 \ g$ of the same substance is ...... $hrs$.

The decay constant of a radioactive sample is $\lambda$. The half-life and mean life of the sample are respectively

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

The half-life period of radioactive decay of ${}^{14}C$ is $5730 \ years$. An archaeological artifact contains $80\%$ of ${}^{14}C$ as compared to a living tree. Calculate the age of the sample in $years$.

If the amount of radioactive substance is increased three times,the number of atoms disintegrated per unit time would