Unpolarized light passes through two ideal Polaroid sheets. The axis of the first is vertical and the axis of the second is at 37.0° to the vertical. What fraction of the incident light is transmitted?

63.78%

Explanation:

The equation that relates the angle of the polarization and the intensity of ligth transmitted is I=Io*cos² (x), where I is the intensity of the incident light, Io is the intensity of the transmitted light, and x is the angle of polarization. The fraction of incident light will be I/Io, so the answer in given by cos² (37) = 0.6378