Parallel Plate Capacitor Energy Stored
The circular plates A and B of a parallel plate air capacitor have a diameter of 0.1 m and are 2 × 10⁻³ m apart. The plates C and D of a similar capacitor have a diameter of 0.12 m and are 3 × 10⁻³ m apart. Plate A is earthed. Plates B and D are connected together. Plate C is connected to the positive pole of a 120 V battery whose negative is earthed. The energy stored in the system is