question_answer

The source producing sound and an observer both are moving along the direction of propagation of sound waves. If the respective velocities of sound, source and an observer are v, \[{{v}_{s}}\]and \[{{v}_{o}}\], then the apparent  frequency heard by the observer will be (n = frequency of sound) [MP PMT 1989]

A)            \[\frac{n(v+{{v}_{o}})}{v-{{v}_{o}}}\]                            

B)            \[\frac{n(v-{{v}_{o}})}{v-{{v}_{s}}}\]

C)            \[\frac{n(v-{{v}_{o}})}{v+{{v}_{s}}}\]                            

D)            \[\frac{n(v+{{v}_{o}})}{v+{{v}_{s}}}\]