The decay constant for a radioactive nuclide is \( 1.5\times 10^{-5} \, \text{s}^{-1} \). Atomic weight of the substance is \( 60 \, \text{g mole}^{-1} \), \( (N_A=6\times 10^{23}) \). The activity of \( 1.0 \, \mu \text{g} \) of the substance is __________ \( \times 10^{10} \, \text{Bq} \).
