The direction of the field is suddenly changed
by an angle of 60º Estimate the heat released by the substance in
aligning its dipoles along the new direction of the field For simplicity,
assume 100% polarisation of the sample Solution   Here, dipole moment of each molecules = 10–29 C m
As 1 mole of the substance contains 6 × 1023 molecules,
total dipole moment of all the molecules, p = 6 × 1023 × 10–29 C m
    = 6 × 10–6
 C m
Initial potential energy, Ui = –pE cos q = –6×10–6×106 cos 0° = –6 J
Final potential energy (when q = 60°), Uf = –6 × 10–6 × 106 cos 60° = –3 J
Change in potential energy = –3 J – (–6J) = 3 J
So, there is loss in potential energy