What is a non-polar molecule?

Explain the behaviour of dielectrics in an external field.

The capacity of a parallel plate capacitor with air is $18 \mathrm{pF}$ When a dielectric material is inserted in the space between the plates, its capacity becomes $108 \mathrm{pF}$.Calculate the permittivity of the material. What is the material?(${\mathrm{\epsilon }}_0=8.854\times {10}^{-12}{\mathrm{C}}^2{\mathrm{N}}^{-1}{\mathrm{m}}^{-2}$)

What is a capacitor? You know that the capacity of a parallel plate condenser is $C=\frac{{\epsilon }_0 A}{d}$. What will be its new capacitance $C\text{'}$ of the capacitor if a material of dielectric $K$ is inserted between the plates? Calculate the capacitance of the capacitor shown below.

Write any five application of superconductors.

In the figure, there are two patterns of electric field lines absent of dielectric [Fig. (a)] and in presence of dielectric slab [Fig. (b)]. The relative permittivity of the dielectric slab is,