A vehicle with a horn of frequency n is moving with a velocity of 30m/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)........ .

A vehicle with a horn of frequency n is moving with a velocity of 30m/

1.	A vehicle with a horn of frequency n is moving with a velocity of 30m/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)........ .
Answer» `n_(1) = 10`n `n_(1) = 0` `n_(1) = -0.1 n` `n_(1) = 0.1` n Solution : No Doppler EFFECT is observed if the SOURCE MOVES perpendicular to the LINE joining the source and the observer. Therefore, the correct choice is (b).