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 half-life of the radioactive isotope tritium $(_1^3H)$ is $12.3 \ years$. If the initial amount of tritium is $32 \ mg$,how many milligrams will remain after $49.2 \ years$ (in $mg$)?

What is the half-life period of a nucleus in $days$ if at the end of $4.2$ $days$,$N = 0.798 \ N_0$?

The radioisotope,tritium $({}_1^3H)$ has a half-life of $12.3 \ years$. If the initial amount of tritium is $32 \ mg$,how many milligrams of it would remain after $49.2 \ years$?

$^{226}Ra$ disintegrates at such a rate that after $3160 \ years$ only one-fourth of its original amount remains. The half-life of $^{226}Ra$ will be .......... $years$.

What is the half-life (in $\text{min}$) of a radioactive substance if $75\%$ of a given amount of the substance disintegrates in $30 \, \text{min}$?