(b) A two-polaroid system is set up with the transmission axis of the second polaroid at 90.0 clockwise from the vertical orientation. A plane-polarised light beam with its initial polarisation direction parallel to the vertical orientation is sent through the system and its final transmitted light is only 25 % of the initial intensity. (i) Determine two possible angles of the first polaroid measured clockwise from its vertical orientation. (6 marks) (ii) An unpolarised light beam is transmitted through the polaroid system in Q1 (b) and the final transmitted light intensity is 50 % of the final transmitted polarised light in Q1 (b). Show that the initial intensity of the unpolarised light is half of the polarised light used in Q1 (b). (4 marks)