The deciding factor will be the strength of the electric field .
If the potential energy of the dipole molecule in the electric field is very much grater than the thermal energy of the molecule,then option (a) is your answer.
If the potential energy of the dipole molecule in...
Basically Fourier series repersentation is applied to functions which are bounded.The next thing is that you have to check for appropriate Dirichlet's conditions.
Thus at the very beginning, a peassumption for applying Fourier series expansion is that the function it represents is always...