The capacitance of a parallel plate capacitor with air as medium is 6$$\mu $$F. With the introduction of a dielectric medium, the capacitance become 30 $$\mu $$F The permittivity of the medium is :
$$\left( {{\varepsilon _0} = 8.85 \times {{10}^{ - 12}}{C^2}{N^{ - 1}}{m^{ - 2}}} \right)$$

A parallel plate capacitor of capacitance 20 $$\mu $$F is being charged by a voltage source whose potential is changing at the rate of 3V/s. The conduction current through the connecting wires, and the displacement current through the plates of the capacitor, would be, respectively :

The electrostatic force between the metal plates of an isolated parallel plate capacitor C having a charge Q and area A, is

A capacitor is charged by a battery. The battery is removed and another identical unchanged capacitor is connected in parallel. The total electrostatic energy of resulting system