This figure, drawn in perspective, shows a system of
three polarizing sheets in the path of initially unpolarized light. The polarizing direction of the first sheet is parallel to the y axis, that of the second sheet is at an angle of 60° counterclockwise from the y axis, and that of the third sheet is parallel to the x axis. We want the fraction of the initial intensity I0 of the light that emerges from the three-sheet system. We also want the polarization direction of that emerging light.