In the circuit shown, the key is inserted at t=0. Charge which passes in the circuit in one time constant is :

Options

A. (a)`L/"VR"`
B. `(LeV)/R^2`
C. `(LV)/(R^2e)`
D. `(L^2V)/(Re)`

Answer

C

Explanation

`i=V/R(1-e^("-t"//tau))`
`q=int_0^tau idt =V/R (1-e^("-t"//tau)/(-1//tau))_0^tau =V/R tau/e =(LV)/(eR^2)`