A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with velocity v meters per sound. The velocity of sound in air is 300 m/s. If person can hear frequencies up to 10000 Hz, the maximum value of v up to which he can hear the whistle is

Options

A. `30 ms^(-1)`
B. `15sqrt(2) ms^(-1)`
C. `15sqrt(2)ms^(-1)`
D. `15 ms^(-1)`

Answer

D

Explanation

`f' = f"(C)/(C - V)`
`10000 = 9500 xx (300)/(300 - V)`

`300 - V = 3 xx 95`
`V = 15 m//s`