Question

what is doppler efect​

Answer 1

an increase in the frequency of sound, light or other waves as the source and observer move towards each other.

Answer 2

Dopper effect is an increase or decrease in the frequency of sound, light, or other Waves as the source and observe moves towards each other. The effect cause the sudden change in pitch noticeable in a passing siren, as well as the red shift seen by astronomers