The Doppler shift explains
A) the phenomenon of beats.
B) why it is that our hearing is best near 3000 Hz.
C) why a sound grows quieter as we move away from the source.
D) why the siren on a police car changes its pitch as it races past us.
E) how sonar works.

Question

Quizplus · Accepted Answer

The Doppler shift describes the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. It explains why the pitch of a siren on a moving vehicle, such as a police car, appears higher as it approaches an observer and lower as it moves away. This is because the sound waves are compressed as the source approaches and stretched as it moves away, changing the perceived pitch.

The Doppler Shift Explains