06-14-2018, 08:37 AM
Most microwave ovens have a wavelength of about 12 cm. This means that you get strong electric fields over the scale of cm, giving you inductive heating and sizable potential differences over macroscopic scales. Visible light, with a wavelength of on the order of 0.00005 cm, will also move electrons around in the foil, but the resistance will be five orders of magnitude less (resistance is proportional to length in a material of constant resistivity), so you won't see such effects.