Question

an electric dipole of dipole moment P is kept parallet to an electric field intensity E. The work done in rotating the dipole through an angle of 90° is
explanation plz

Answer 1

since potential energy stored in a dipole in an uniform electric field is..u=[cosA1+cosA2]..if dipole start rotating from 90° then cosA1=90° whose value is zero....and hence the work done should be equal to...u=—PE CosA