A parallel plate capacitor having capacitance `0.5mu` is taken. Plates are given charges as shown in the figure. When key is open the energy stored in capacitor is `U_(1)` % when key is closed the enrgy stored bucome `U_(2)` Find. `(U_(1))/(U_(2))` ?

Options

A. `1:1`
B. `1:2`
C. `2:1`
D. `1:3`

Answer

A

Explanation

`C= 0.5muF `
`U _(1) =(Q_(2))/(2c) =((1 mu C)^(2))/(2xx0.5muF )=1 mu J`

`U_(2) =1/2CV ^(2) =1/2 xx0.5mu F xx(2) ^(2) = 1 muJ`
`(U_(1))/(U_(2))=1/1`