A battery is used to charge a parallel plate capacitor till the potential differece between the plates becomes equal to the electromotive force of the battery. The ratio of the energy stored in the capacitor and the work done by the battery will be

Options

A. `1//2`
B. 1
C. 2
D. `1//4`

Answer

A

Explanation

(a) Required ratio
`= (Energy stored in capacitor )/(Workdone by the battery) = (1/2CV^2)/(Ce^2)`
where C = Capacitance of capacitor
V = Potential difference
e = emf of battery.
`= (1/2Ce^2)/(Ce^2) = 1/2` `(.: V=e)`.