Doppler effect

 Q #What is the Doppler effect? Find out the expression of apparent changed frequency for the following cases :

   1. When the observer moves  towards the stationary source.

   2. When the observer moves away from the stationary source.

   3.When the source moves towards the stationary observer.

   4. When the source moves away from stationary observer.

DOPPLER'S EFFECT

                          The apparent change in the frequency of  sound  due to relative motion between the observer and sourse of the sound is called Doppler Effect.

      Suppose a source of sound emitts a sound of frequency f and wavelength λ . Let the velocity of the sound in medium is ν . If the source and onserver are stationary ,the number of waves observered by the observer in one second are :

        f =υ/λ

      we want find out the expression of apparent change in the frequency of sound due to the relative motion between aource and observer.

Case 1. When the observer moves tiwards the sttionry sourve.

              Let the observer A moves towards  the stationary source with velocity u₀ then the relative velocity of the waves and the observer is increased to (ν+u₀).Then the frequncy of sound recived by the onserver A is 

          fₐ=ν+u₀/(ν/f)