lc99 said:
The Doppler Effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.
The Doppler Effect is caused by the relative motion between the source of the wave and the observer. If the source and observer are moving closer together, the frequency of the wave increases. If they are moving farther apart, the frequency decreases.
The Doppler Effect for sound waves occurs when there is relative motion between the source of the sound and the observer, while the Doppler Effect for light waves occurs when there is relative motion between the source of the light and the observer.
The Doppler Effect is used in various applications such as radar, sonar, and medical imaging. It is also used in traffic speed cameras and radar guns.
The sound of a siren from an emergency vehicle becoming higher pitched as it approaches and then lower pitched as it moves away is an example of the Doppler Effect. Another example is the changing pitch of a train horn as it passes by.
