Wave impedance in a vacuum

This article reminds us that this constant is often misinterpreted due to an inappropriate unit conversion that gives it the dimension of a resistance. It emphasizes that the choice of the fields E and H is only useful for accounting for reflection or transmission phenomena when the propagation medium changes, and does not reveal the deeper meaning of this constant. A study based on the physical roles of the fields E and H shows that this ratio represents only a mechanical effect, as would the B/D ratio. The integration of recent developments (the resolution of the inconsistency in the initial laws of electromagnetism) establishes that it is in fact an electromechanical coupling constant. It can be verified that it appears in all electromagnetic relationships that result in a mechanical effect (it appears, among other things, in the expressions for Ampère’s and Coulomb’s forces). It proves to be of considerable importance.