contestada

The following items are positioned in sequence: A source of a beam of natural light of intensity I0, three ideal polarizers A, B, and C; and an observer. Polarizer axis angles are measured clockwise from the vertical, as viewed by the observer. The axis angle of polarizer A is set at 0° (vertical), and the axis angle of polarizer C is set at 50°. The axis angle of polarizer B is set at 120°. What is ratio of the intensity of the beam at the observer to the intensity I0 of the source?