Physics (AS & A Level) · May / June 2026 · Paper 13 · Question 25

Plane polarised light of intensity I is incident normally on a set of polarising filters. The transmission axis of the first filter is at 30° to the plane of polarisation of the incident light. The transmission axis of each successive filter is at 30° to the transmission axis of the previous filter. The intensity of the light emerging from the final filter is 0.24I. How many polarising filters are in the set?

1. A3
2. B5
3. C6
4. D10

As printed in the paper