When unpolarized light is polarized with two polarizers, the intensity is reduced in according to Malu's law. But..... when unpolarized light is polarized with only one polarizer, the intensity is reduced to half the intensity of the unpolarized light. Why? I've read that unpolarized light had electric-field vectors in all possible directions, but I dont understand the idea of resolve them in only two components, one parallel to polarizer's axis and the other perpendicular to it. (sorry my bad english).