Doppler Effect Calculator
Calculate the observed frequency when a sound source and observer are in relative motion using the Doppler formula.
Observed Frequency
482.17 Hz
Observed Frequency vs Source Frequency
Fórmula
## Doppler Effect The Doppler effect is the change in observed frequency caused by relative motion between source and observer. ### Formula **f_obs = f_source * (v_sound + v_observer) / (v_sound - v_source)** Sign convention: speeds are positive when source and observer move toward each other.
Ejemplo Resuelto
An ambulance siren at 440 Hz approaches a stationary observer at 30 m/s.
- 01f_obs = f_s * (v + v_o) / (v - v_s)
- 02f_obs = 440 * (343 + 0) / (343 - 30)
- 03f_obs = 440 * 343 / 313
- 04f_obs = 482.2 Hz
Preguntas Frecuentes
Why does a siren sound higher-pitched as it approaches?
The sound waves are compressed in front of the moving source, shortening the wavelength and increasing the observed frequency.
Does the Doppler effect apply to light?
Yes, but the relativistic Doppler formula must be used for light since light speed is constant in all reference frames.
What happens when source speed equals the speed of sound?
The denominator becomes zero, meaning infinite observed frequency. This corresponds to a sonic boom (shock wave).
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