Question

Four polarizers are placed in succession with their axes vertical, at 45° to the vertical, at 60.0° to the vertical, and at 75° to the vertical.

a. Calculate what fraction of the incident polarized light is transmitted by the four polarizers. b. Can the transmitted light be decreased by removing one of the polarizers? If so, which one? c. Can the transmitted light intensity be extinguished by removing polarizers? If so, which one(s)?

Side note: I understand how to solve this problem from an instance in which it is unpolarized light, however I am confused how to treat this problem if the light is polarized.

Answer 1

If polarized light in incident on the polarizer then the intensity of transmitted light is given by the Malu's law I I cos2e where 0 is the angle between the axis of the polarizer and the direction of polarization of incident light Amount of transmitted light Let e be the angle between the direction of polarization of light and the axis of the first polarizer. Then the intensity of light transmitted after all polarizers a. I I, cos' excos (45) cos2 (15) xcos (15) COS 0.4351, cos2 e 0.4351 cos2e -x100 Fracti on of light transmitted through -x 100 = 43.5cos2 e We need to know the angle to proceed further b. Transmitted light can still be reduced if we remove the polarizer which is kept at an angle 60° to the vertical Transmitted light intensity cannot be extinguished by removing any of the polarizers Removal of polarizers doesn't make the light polarization stated crossed with any of the remaining polarizers c