On the same path, the source and observer are moving such a way that the distance between these two inicreases with the time. The speeds of source and observer are same and equal to `10ms^(-1)` with respect to the ground while no wind in blowing. The apparent frequency received by observer is `1950 Hz` then the original frequency must be (the speed of sound in present medium is `340 m//s`

Options

A. `2068Hz`
B. `2100Hz`
C. `1903Hz`
D. `602Hz`

Answer

A

Explanation

Here,`upsilon_(L)=upsilon_(S)=10ms^(-1), v^(')=1950Hz,`
`upsilon=340m//s`
Let the original frequency be `v`. Apparent frequency when source and observer are movign away from each other is giveny by
`v^(')=((upsilon-upsilon_(L))/(upsilon+upsilon_(S)))v`
`1950=(340-10)/(340+10)v` or `v=(1950xx350)/(330)`
`v=2068.18Hx~~2068Hz`