Define the activity of a radio nuclide. Write its S.I. unit. Give a plot of the activity of a radioactive species versus time.
How long will a radioactive isotope, whose half life is T years, take for its activity to reduce to `1//8`th of its initial value ?

Explanation

The total decay rate R of a sample of one or more radio nuclide is called the activity of that sample. The SI unit for activity is Bequrel.
1 bequrel =1 Bq =1 decay per second.
Graph : The graph between the activity of a radioactive species and time is shown in Fig.

Time taken for activity of a radioactive isotope to reduce to `1/8` th of its initial value
`=3T_(½)=3 T" "( :' T_(½)=T)`