doppler effect
1
the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the source of the wave, producing a shift in pitch or color
- The Doppler effect explains why the pitch of an ambulance siren changes as it approaches and then passes by.
- When a car with a honking horn drives by, the change in pitch you hear is due to the Doppler effect.
- In astronomy, the Doppler effect helps scientists determine the speed and direction of celestial objects.
- The color shift in the light from a moving star is an example of the Doppler effect in astrophysics.
- The Doppler effect is employed in police radar guns to measure the speed of moving vehicles.
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