Physics for IGCSE & O level - Waves And Sounds (Section 3 - No. 39)
What causes the Doppler effect?
Changes in the amplitude of a wave.
The relative motion between the source of a wave and an observer.
The interference of two waves.
The reflection of a wave.
ব্যাখ্যা
The Doppler effect is due to relative motion between the source and observer.