In AC field, polar molecule are trying to align with external field. At high freguencies, changes of field are so quict, that molecules cannot align with it. This leads to increasing kinetic energy of molecules, therefore heating.
My question is this:
Is increase of kinetic energy caused 1) by transforming some portion of energy from EM field (= dipole molecules absorbs EM energy, which is then converted into kinetic energy), or 2) by simple presence of external field? (= the source of kinetic energy is not external field - ie. no energy absorbed, therefore no dielectric loss and so no energy transformed from external field)?
Could you please clarify the exact pathway by which is this happening?