A stationary source emits sound of frequency 1200 Hz. If would blows at the speed of 0.1 v. deduce
(a) The change in the frequency for a stationary observer on the wind side of the source
(b) Report the calculations for the case when there is no wind but the observer moves at 0.1 v speed towards the source (Given : velocity of sound = v)

Explanation

(a) Medium moves in the direction of sound propagation i.e, from source to observer si effective velocity of sound `v_("eff") = v + v_(m)`
since both source and observer are at rest `n'=((V+V_(m)+0)/(V+V_(m)+0))n=((V+0.1V)/(V+0.1V))n=n`
So there is no change in frequency
(b) When ovbserver move towards source `n'=((v+v_(0))/(v))n=((v+0.1v)/(v))n`
`=1.1 n=1.1xx1200Hz=1320Hz`.