Physics (AS & A Level) · May / June 2023 · Paper 13 · Question 24

A source of plane polarised light is observed through two polarising filters. The filters are positioned so that the source appears at its brightest. One of the filters is then rotated clockwise and the other filter is rotated anticlockwise through the same angle. How does the source appear when both filters have been rotated 90° and 180° from their initial positions?

1. A90°: brightest, 180°: brightest
2. B90°: brightest, 180°: darkest
3. C90°: darkest, 180°: brightest
4. D90°: darkest, 180°: darkest

As printed in the paper