Optics & Waves
Advanced

Doppler Effect (Sound)

Observed frequency shift from relative motion.

Formula

f′=fv±vov∓vsf' = f\frac{v \pm v_o}{v \mp v_s}

Variables

vSound speed
v_oObserver speed
v_sSource speed

Did You Know?

The Doppler effect is why an ambulance siren drops in pitch the instant it races past you.

dopplersoundfrequency