The activity of a radioactive susbtance is `R_(1)` at time `t_(1)` and `R_(2)` at time `t_(2)`(>t1). its decay constant is λ. Then, number of atoms decayed between time interval `t_(1)` and `t_(2)` are

Options

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

Answer

d

Explanation

`R_(1) =lambdaN_(1) rArr N_(1) =(R_(1))/(lambda)`
and `R_(2) =lambdaN_(2)rArr N_(2) =(R_(2))/(lambda)`
Therefore, number of atoms decayed `=N_(1)-N_(2) =((R_(1)-R_(2))/(lambda))`.