Physics - Modern Physics Question with Solution | TestHub

In 9 years, activity becomes$\text{I}=\frac{{\text{I}}_0}{3}$

In further 9 years, activity would becomes

${\text{I}}^{\prime }=\frac{\text{I}}{3}=\frac{{\text{I}}_0}{3\times 3}=\frac{{\text{I}}_0}{9}$