Physics (AS & A Level) · May / June 2026 · Paper 13 · Question 24

A loudspeaker moves with a constant speed relative to a stationary observer. The loudspeaker emits a sound of constant frequency. The frequency of sound observed depends on the speed and the direction of motion of the loudspeaker. Which motion of the loudspeaker will cause the highest observed frequency?

1. Aaway from observer, 10 m s–1
2. Baway from observer, 5 m s–1
3. Ctowards observer, 10 m s–1
4. Dtowards observer, 5 m s–1

As printed in the paper