Question
A parallel plate capacitor of capacitance C is charged to a potential V. It is then connected to another uncharged capacitor having the same capacitance. Find out the ratio of the energy stored in the combined system to that stored initially in the single capacitor.
Solution
Energy stored in a capacitor is given by,
When capacitor is connected in parallel combination, equivalent capacitance = 2C
Here, total charge Q remains the same.
Initial energy is given by,
Final energy is given by,
So, the ratio of energy is given by,