Physics (AS & A Level) · May / June 2024 · Paper 13 · Question 26

A student investigates the polarisation of microwaves. The microwaves from the transmitter are vertically polarised. A metal grille acts as a polarising filter when placed between the microwave transmitter and the receiver. The reading on the voltmeter is proportional to the intensity of microwaves transmitted through the grille. When the transmission axis of the grille is vertical, the voltmeter reads 3.50 V. [diagram: transmitter, metal grille, receiver, voltmeter] The grille is then rotated through an angle θ. The voltmeter now reads 2.20 V. What is θ?

1. A37.5°
2. B39.0°
3. C51.0°
4. D52.5°

As printed in the paper