Activity of a radioactive substance is `R_(1)` at time `t_(1) ` and `R_(2)` at time `t_(2) (t_(2) gt t_(1))` then the ratio `(R_(2))/( R_(1))` is :

Options

A. `(t_(2))/( t_(1))`
B. `e^(-lambda(t_(1)+t_(2)))`
C. `e ( (t_(1) - t_(2))/( lambda))`
D. `e^(lambda( t_(1) - t_(2)))`

Answer

D