Physics (AS & A Level) · May / June 2021 · Paper 11 · Question 21

Two identical waves are produced by sources at points P and Q. The waves travel along different paths to reach point R, as shown. Both waves have a wavelength of 6.0 cm. The waves are in phase at point R. What is the phase difference between the waves as they leave points P and Q?

1. A0°
2. B60°
3. C90°
4. D120°

As printed in the paper