2. When a ray of light is incident on two polarizers with their polarization axes perpendicular, no light is transmitted. If a third polarizer is inserted between these two with its polarization axis at 45° to that of the other two, does any light get through to point P?
1. yes
2. no
Answer: 1.The light transmitted by the first polarizer has its polarization
vector oriented vertically. So, while no light is transmitted through a polarizer
that is oriented horizontally, some light is transmitted through the
third polarizer at 45°. The light transmitted by polarizer 3 has its polarization
vector at 45°, and thus some light passes through (the horizontally
oriented) polarizer 2.

3. 3. the same amount of light 4. more light gets through.
When a third polarizer is inserted at 45° between two orthogonal polarizers, some light is transmitted. If, instead of a single polarizer at 45°, we insert a large number N of polarizers, each time rotating the axis of polarization over an angle 90° / N,
1. no light
2. less light
3. the same amount of light
4. more light gets through.
Answer: 4. The smaller the angle between two successive polarizers, the
larger the amount of transmitted light.
The smaller the angle between two successive polarizers, the larger the amount of transmitted light.

4. CH 5: Superposition