Question

7. A sample constant 4.5 x 1018 atoms of a radioactive isotope . If it has a decay constant of 1.1 x10-12 s-1, what is the activity of the sample ? 

Answer 1

$A=\lambda N=1.1\cdot10^{-12}\cdot4.5\cdot10^{18}=4950000\ (Bq)=4.95\cdot10^6\ (Bq)$