During mean life of a radioactive element, the fraction that disintegrates is

Options

A. e
B. `(1)/(e)`
C. `(e-1)/(e)`
D. `(e)/(e-1)`

Answer

C

Explanation

`N= N_(0)e^(- lamda t) rArr N = (N_(0))/(e) (" at " t= tau = (1)/(lamda))`
Disintegrated fraction `=1 - (N)/(N_(0))= 1- (1)/(e)= (e- 1)/(e)`