question_answer

A radioactive sample having N nuclei has activity R. Write down an expression for its half-life in terms of R and N.          

Answer:

                Activity, \[R=N\lambda \]                 \[\therefore \] Disintegration constant,  \[\lambda =\frac{R}{N}\]                 Half-life, \[{{T}_{1/2}}=\frac{0.693}{\lambda }=\frac{0.693N}{R}\].