# I Doppler shift and change in intensity of a sound wave

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1. Jul 4, 2016

### Soren4

How are the intensity of a sound wave and the Doppler shift of frequency related togheter?
That is, if the source or the observer are in relative motion, how does the intensity change?

For a sound wave $$I=\frac{1}{2} \rho \omega^2 A^2 c=2 \pi^2 \rho f^2 A^2c$$

($c$ is sound speed, $\rho$ is density of air, $A$ is amplitude)

So, since Doppler effect is only about $f$, I would say that

$$I'=I \bigg(\frac{f'}{f}\bigg)^2=I \bigg(\frac{c+v_{oss}}{c+v_{sorg}}\bigg)^2$$