A sound source moving with speed 50 m/s along x-axis and observer at rest on y-axis.If the frequency observed by observer when source crosses the origin is 96 Hz, then the original frequency of source is :(speed of sound is given medium is 200 m/s)

Options

A. 90 Hz
B. 100 Hz
C. 80 Hz
D. 60 Hz

Explanation

Sound emitted by source at S which is observed by observed by observer when source crosses origin.
Then `Costheta=(50t)/(200t)=1/4`
`96=f((200-0)/(200-50costheta))`
f=90 Hz