Incident light passes through a polaroid filter and becomes polarized. the best description of the role of the filter is to state that it serves to

It serves to polarization by transmission through a filter. A Polaroid filter is a device used to polarize light. The device filters out one-half of the vibrations of unpolarized light as the light passes through the filter. Unpolarized light enters the Polaroid filter and the polarized light goes out from the filter. The unpolarized light becomes polarized.