A vehicle, with a horn of frequency n is moving with a velocity of 30 m/s in a direction perpendicular to the straight line joining the observer and the vehicle. The observer perceives the sound to have a frequency `n + n_(1)`. Then (if the sound velocity in air is 300 m/s)

Options

A. `n_(1)=10n`
B. `n_(1)=0`
C. `n_(1)=0.1n`
D. `n_(1)=-0.1n`

Answer

B

Explanation

As the source moves `bot^(lr)` to the line joining the observer and hence no doppler effects i.e.,
`n.=nimpliesn_(1)=0`