Answer and Explanation:
Doppler effect : According to Doppler effect whenever there is a relative motion between the source and observer then there is an increase or decrease in frequency of sound light or waves.
REASON OF DOPPLER EFFECT : Doppler effect is mainly due to the sudden change in pitch of the sound
EXAMPLE OF DOPPLER EFFECT : The best example of Doppler effect is when an ambulance passes and when it comes closer then the frequency of the siren increases and when it goes away its frequency decreases.
