The true physical significance of the electric field emerges when we deal with the electromagnetic phenomenon.

An electric dipole is formed by two charges $q$ and $-q$ placed at the two ends of an insulating rod of length $d$ and negligible mass. Write down the dipole moment. Is it a vector or a scalar? The dipole is then placed in a uniform electric field and is given a small angular displacement $\mathrm{\theta }$ from its equilibrium position. What are the total force and torque acting on it?

Define dielectric constant. What do you mean by the statement - dielectric constant of mica is $6$?

The mutual force of repulsion between two point charge having fixed distance between them is $9$ Dyne in vacuum and $4$ Dyne in a dielectric medium. What is the dielectric constant of the medium.

A sphere of metal has a radius of $12 \mathrm{cm}$ and carries a charge of $1.6\times {10}^{-7}\mathrm{C}$, distributed uniformly on its surface. Calculate the electric field intensity at a point just outside the sphere.