Question

A capacitor is charged with a battery and energy stored is U. After disconnecting battery another capacitor of same capacity is connected in parallel with it. Then energy stored in each capacitor is:

Answer 1

Final Answer : U/4

STEPS:

1) Initially, Let the charge on capacitor be Q.

Then,

Energy Stored : Q^2/2C

2) After disconnecting the battery and connecting other identical capacitor parallel to it.

Now, Charge will flow in such a way that total charge is Q and potential difference across both capacitor remains same.

Hence,

Potential difference across each capacitor,

V = Q/2C

3) Then, Energy in each capacitor :

1/2C V^2

=>( 1/2 )C * (Q/2C)^2

=> (1/4 )* (1/2 Q^2/C)

=> 1/4U

Hence, Energy Stored in each capacitor becomes U/4 .