Question

A capacitor of capacitance C has charge Q. It is connected to an identical capacitor through a resistance. The heat produced in the resistance is 

(a) Q²/2C 

(b) Q²/4C 

(c) Q²/8C

(d) dependent on the value of the resistance

Answer 1

Correct Answer is: (b) Q²/4C

As the capacitors are identical, they will finally have charge Q/2 each.

Initial energy of the system = E_i = Q²/2C.

Final energy of the system = E_f = 2 [Q/2)² / 2C] = [Q²/4C].

Heat produced = loss in energy = E_i = E_f = Q²/4C.