A wave plate or retarder is an optical devicethat alters the polarization state of a light beam traveling through it. In thepresent setup, halogen light source with yellow light filter passes through apolarizer to produce linear polarized light. This polarized light then falls ona quarter wave plate L/4. The emergent light passes through analyser. It isinvestigated at different angles of L/4 plate ( 0degree, 30 degree, 45 degree,60 degree and 90 degree) between the optic axis of the wave plate and thedirection of the incident light. The light intensity can be investigated withthe analyser over the range -90 degree to +90 degree. At 0 degree and 90 degreeof L/4 with respect to optic axis, the transmitted light is linearly polarized,at 45 degree it is circularly polarized, and at 30 degree and 60 degree it iselliptically polarized.