If the potential of a capacitor having capacity of `6 muF` is increased from 10 V to 20 V,then increase in its energy will be

Options

A. `12 xx 10^(-6) J`
B. `9 xx 10^(-4) J`
C. `4 xx 10^(-6) J`
D. `4 xx 10^(-9) J`

Answer

B

Explanation

The increase in energy of the capacitor
`DeltaU = (1)/(2) C(V_(2)^(2) - V_(1)^(2)) = (1)/(2) (6 xx 10^(-6)) (20^(2) - 10^(2))`
`= 3 xx 10^(-6) xx 300 = 9 xx 10^(-4) J`