When electric dipole is placed in uniform electric field, its two charges experience equal and opposite forces which cancel each other and hence net force on electric dipole in uniform electric field is zero. However, these forces are not collinear, so they give rise to some torque on the dipole. Since net force on electric dipole in uniform electric field is zero. so, no work is done in moving the electric dipole in uniform electric field. However, some work is done in rotating the dipole against the torque acting on it. 

 

An electric dipole of moment p is placed in an electric field of intensity E. The dipole acquires a position such that the axis of the dipole makes an angle 𝜃 with the direction of the field. Assuming that the potential energy of the dipole to be zero when $\mathrm{\theta }={90}^{\mathrm{o}}$, the torque and the potential energy of the dipole will respectively be