What Is Meant By Dielectric Constant.

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.

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,

For the metallic conductor

In the figure, a solid sphere of the radius $a=2.00 \mathrm{cm}$ is concentric with a spherical conducting shell of inner radius $b=2.00a$ and outer radius $c=2.40a$. The sphere has a net uniform charge $q_1=+5.00 \mathrm{C}$, the shell has a net charge $q_2=-q_1$. What is the net charge on the inner surface of the shell?