A capacitor is charged to store an energy U. The charging

Home » Electrostatics » Electrostatic Potential and Capacitance » Question

A capacitor is charged to store an energy U. The charging battery is disconnected. An identical capacitor is now connected to the first capacitor in parallel. The energy in each of the capacitor is

1. U/2
2. 3U/2
3. U
4. U/4

Correct Option: A

In Ist case when capacitor C connected with battery charged with the energy,
U₁ = U (stored energy on capacitor).
In IInd case, after disconnection of battery similar capacitor is connected in parallel with Ist capacitor then C_eq.=C' = 2C.

Now,		=	1	q²	=
	U₁		2	C		C'

	U₂		1	q²		C

			2	C'

=	2C	(∵ C' = 2C)
	C

U₂ =	U
	2