A polaroid (I) is placed in front of a monochromatic source. Another polaroid (II) is placed in front of this polaroid (I) and rotated till no light passes. A third polaroid (III) is now placed in between (I) and (II). In this case, will light emerge from (II). Explain.

Question

Philoid · Accepted Answer

Here polaroid (II) is placed in front of polaroid (I) such that no light passes i.e. they are making an angle of 90° with each other. When the pass axis of polaroid (III) is parallel with polaroid (I) or polaroid(II) light will not emerge from polaroid(II).All other cases light will emerge from polaroid(II).