11. You have to look at the skin depth . 12. In a good conductor, skin depth is proportional to square root of the resistivity. 13. The overall resistance of the better conductor remains lower even with the reduced skin depth . 14. Skin depth also varies as the inverse square root of the permeability of the conductor.15. For effective shielding from a magnetic field, the shield should be several skin depths thick. 16. Especially interesting how the higher the frequency, the thinner the skin depth necessary to shield. 17. There are also physical limits to generating eddy currents and depth of penetration ( skin depth ). 18. At some microwave wavelengths, the skin depth is less than the thickness of even the thinnest foil. 19. The surface resistance in a thick metal conductor is proportional to the resistivity divided by the skin depth . 20. Household foil is much thinner than the skin depth in aluminum at the frequencies used by an induction cooker.
