The activity of a sample of radioactive material `A_(1)` at time `t_(1)` and `A_(2)` at time `t_(2)(t_(2)gtt_(1))`. Its mean life is `T`.

Options

A. `A_(1) t_(1) =A_(2) t_(2)`
B. `( A_(1) + A_(2))/(t_(2) - t_(1))=` constant
C. `A_(2) = A_(1)e^((t_(1) - t_(2))//T)`
D. `A_(2) = A_(1)e^((t_(1) //T t_(2)))`

Answer

C