A dipole is made up of two charges + q and - q separated by a distance 2a. Derive an expression for the electric field due to this dipole at a point distance r from the centre of the dipole on the equatorial plane. Draw the shape of the graph, between | Ee | and r when r > >a. If this dipole were to be put in a uniform external electric field obtain an expression for the torque acting on the dipole.