Hello everyone, if an electric field in a medium with permittivity eps_1 moves at an angle into a material with eps_2, there is refraction. The field in the second medium changes angle. we can see that the tangential component is not changed but the one normal to the surface of separation is changed by a factor equal to eps_1/eps_2. If that happens, the magnitude of the electric field (its length) changes when we get in the second medium. But we have not assume that the media were lossy. guess the decrease is due to the polarization. Once out of the second medium, the E field magnitude returns to its initial value. Is that correct? thanks!