A parallel plate capacitor of capacitane C is charged to a potential V. It is then connected to another uncharged capacitor with the same capacitance. Find out the ratio of the energy stored in the combined system to that stored initially in the single capacitor.

Explanation

Initial energy , `U=(1)/(2)Cv^(2)" "...(i)`
Common potential of combined system V' `=(C-V+C*O)/(C+C)=(V)/(2)`
Energy store in combined system U' `=(1)/(2)(C+C)V'2=(1)/(2).2C.(V^(2))/(4)" "...(ii)`
From (i) and(ii) `(U)/(U)=1:2`