-In the figure above,some wavefronts are emitted by a source of sound S.This picture can help us to understand
A)why the siren on a police car changes its pitch as it races past us.
B)why a sound grows quieter as we move away from the source.
C)how sonar works.
D)the phenomenon of beats.
E)why it is that our hearing is best near 3000 Hz.

Question

-In the figure above,some wavefronts are emitted by a source of sound S.This picture can help us to understand
A)why the siren on a police car changes its pitch as it races past us. 
B)why a sound grows quieter as we move away from the source. 
C)how sonar works. 
D)the phenomenon of beats. 
E)why it is that our hearing is best near 3000 Hz.

Quizplus · Accepted Answer

The change in pitch of a siren as it moves past is explained by the Doppler effect, which is related to the change in frequency of wavefronts as the source moves relative to an observer.

-In the Figure Above,some Wavefronts Are Emitted by a Source