A molecule of a substance has a permanent electric dipole moment of magnitude `10^(-30)` Cm. A mole of this substance is polarised (at low temperature) by applying a strong electrostatic field of magnitude `10^(7) vm^(-1)`. The direction of the field is suddenly changed by an angle of `60^(@)`. Estimate the heat released by the substance in aligning its dipole along the new direction of the field. For simplicity assume 100 % polarisation of the sample. 1 mole `= 6 xx 10^(23)` molecule.

Explanation

`DeltaU = 3J`