A capacitor is charged by a battery. The battery is removed

A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :

1. decreases by a factor of 2
2. remains the same
3. increases by a factor of 2
4. increases by a factor of 4

When battery is replaced by another uncharged capacitor

As uncharged capacitor is connected parallel
So, C' = 2C

and V_c =	q₁ + q₂
	C₁ + C₂

V_c =	q + 0
	C + C

⇒ V_c =	V
	2

Initial Energy of system, U_i =	1	CV²..........(i)
	2

Final energy of system, U_f =

=	1	(2C)		V		²
	2			2

=	1	CV²		1		.......(ii)
	2			2

From equation (i) and (ii)

U_f =	1	U_i
	2

i.e., Total electrostatic energy of resulting system decreases by a factor of 2