question_answer

 A vehicle with a horn of frequency n, is moving with a velocity of \[30\,m{{s}^{-1}}\] in a direction perpendicular to the straight line joining the observer and the vehicle. The observer receive the sound to have a frequency \[n+{{n}_{1}}\]. Then (if the sound velocity in air is \[300\,m{{s}^{-1}}\])

A) \[{{n}_{1}}=10n\]

B)                       \[{{n}_{1}}=0\]                 

C) \[{{n}_{1}}=0.1\,n\]       

D)                       \[{{n}_{1}}=-0.1n\]