Question

What is the effect of dielectric when capacitor is connected or disconnected with battery???
Plz it's urgent

Answer 1

A parallel plate capacitor is charged by a battery, which is then disconnected. A dielectric slab is then inserted in the space between the plates. Explain what changes, if any, occur in the values of:

Answer 2

Q = C * V

    Q  = charge on the capacitor plates (each)

    V = voltage across the plates

    C = capacitance of the capacitor

C = ε A / d  ,  Where A = area of each of the plates

                        d = distance between the plates.

                        ε = permittivity of the medium in between the plates.

 If the distance d increases, then the capacitance C decreases.  As a consequence, the charge on the capacitance is not affected.  So Voltage difference between the plates increases.

Electrostatic energy = 1/2 C V² = 1/2 Q V = Q² / 2 C

    So as the capacitance decreases, the electrostatic energy increases.  The work done in moving the capacitor plates against electrostatic attraction, is stored in the capacitor as electrostatic potential energy.