Question

A parallel plate capacitor is an arrangement of two identical metal plates kept parallel, a small distance apart. The capacitance of a capacitor depends on the size and separation of the two plates and also on the dielectric constant of the medium between the plates. Like resistors, capacitors can also be arranged in series or parallel or a combination of both. By virtue of electric field between the plates, charged capacitors store energy.

The capacitance of a parallel-plate capacitor depends on:

Read the following statements about a parallel-plate capacitor and identify the correct option: (I) The capacitance of a parallel-plate capacitor in vacuum is given by C = ε0A/d, where A is the area of each plate and d is the separation between them. (II) When a dielectric slab of dielectric constant K is fully inserted between the plates, the capacitance becomes K times its earlier value. (III) The energy stored per unit volume (energy density) in the electric field between the plates (in vacuum) is u = ½ ε0E². (IV) If the plates of an isolated charged capacitor are pulled farther apart at constant charge, the energy stored in the capacitor decreases.

In a parallel plate capacitor with air between the plates, each plate has an area of 6 × 10–3 m2 and the distance between the plates is 3 mm. Calculate the capacitance of the capacitor. If this capacitor is connected to a 100 V supply, what is the charge on each plate of the capacitor?