where, A= area of the plates, d= separation between the plates Charge stored in the capacitor, Q=C0V0 When battery is disconnected, then charge remains same. So, energy, E1=
1
2
Q2
C
C= capacitance when plate separation is doubled So, C1=
C0
2
E1=
1
2
Q2
C0∕2
=
Q2
C0
=
C02V02
C0
=C0V02 When battery is connected, then Energy, E2=