Question

A horn producing a sound of frequency 540
Hz is moving towards a stationary observer
with a speed of 33m/sec if the velocity of sound
in air is 330m/sec then the frequency heard
by an observer will be:
​

Answer 1

the question says that the source is moving towards a stationary observer...........which means that obviously the frequency heard by the observer would be greater than the real frequency...

the formula for the question is:

n' =  n[v -  vo] / [v + vs]

                                    here n' = frequency heard by observer

                                             n = 540 Hz

                                             v  = velocity of sound

                                             vo = velocity of observer (0 in this case)

                                              vs = velocity of source

n' = 540[330]/[330+30]

n' = 540 * 330 / 360

n'   = 495 Hz  

               

i hope u get that.....