The decay constant for a radioactive nuclide is $1.5\times {10}^{-5}{\mathrm{s}}^{-1}$. Atomic weight of the substance is $60{\mathrm{gmole}}^{-1}$. $\left({\mathrm{N}}_{\mathrm{A}}=6\times {10}^{23}\right)$ . The activity of $1.0\mathrm{\mu g}$ of the substance is $\times {10}^{10}\mathrm{Bq}$.