Given, for an electric dipole, θ1=30∘ θ2=90∘ ∴ Work done in rotating the dipole from θ1=30∘ to a position, where its axis is perpendicular (θ2=90∘) to electric field is given as W=pE(cos‌θ1−cos‌θ2) =pE(cos‌30∘−cos‌90 =pE(‌