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?
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