Hey. If a wire is conducting electricity and all the current is concentrated at the edge of the wire, as in the skin effect, the magnetic field everywhere inside should be zero due to symmetry when applying biot-savarts law. However, according to ampere's law, it shouldn't. I take a cross-section of the wire and apply an annulus surface where the the outer ring covers the current I penetrating the cross-section, while the inner ring defines the integral ∫B*dl. The radius of the inner ring is r. Then ∫B*dl = Iμ => B = Iμ/2pi*r How is this contradiction possible? Am I applying ampere's law wrong?