Power
Dielectric heating must be distinguished from Joule heating of conductive media, which is caused by induced electric currents in the media. For dielectric heating, the generated power density per volume is given by
where is the angular frequency of the exciting radiation, is the imaginary part of the complex relative permittivity of the absorbing material, is the permittivity of free space and the electric field strength. The imaginary part of the (frequency-dependent) relative permittivity is a measure for the ability of a dielectric material to convert electromagnetic field energy into heat.
If the conductivity of the material is small, or the frequency is high, such that (with ), then dielectric heating is the dominant mechanism of loss of energy from the electromagnetic field into the medium.
Read more about this topic: Dielectric Heating
Famous quotes containing the word power:
“Great is Truth, and mighty above all things.”
—Apocrypha. 1 Esdras, 4:41.
Acclamation following the speech of the bodyguard of King Darius, who proclaimed the power of truth, “the strength, kingdom, power, and majesty of all ages.”
“Failure or success seem to have been allotted to men by their stars. But they retain the power of wriggling, of fighting with their star or against it, and in the whole universe the only really interesting movement is this wriggle.”
—E.M. (Edward Morgan)
“Who would not give up wit for power and beauty?”
—Mason Cooley (b. 1927)