Physics (AS & A Level) · May / June 2023 · Paper 13 · Question 22

A vehicle moves with constant velocity along a road directly towards an observer. The observed frequency of the sound from the vehicle changes as the vehicle moves past the observer. Which phenomenon explains the change in frequency?

1. Adiffraction
2. Binterference
3. Cpolarisation
4. Dthe Doppler effect

As printed in the paper