Problem 14: If C₁ = 14 µF, C₂ = 20 µF and C₃ = 12 µF and the insulated plate of C₁ be at a potential 100V while one plate of C₃ being earthed. What is the potential difference between the plates of C₂ when the three capacitors are connected in series?

Solution

Earth is referred to be at 0 potential. Thus the potential applied to the system of capacitors is 100 V.

We find the equivalent capacitance and the charge on the capacitors. In series combination of capacitors, the equivalent capacitance is

Therefore, the equivalent capacitance of the combination is

The charge on each capacitor will be same, given by,

The potential difference between the plates of C₂