A vehicle , with a horn of frequency `n` is moving with a velocity of `30 m//s` in a direction prependicular to the straight line joining the observer and the vehicle . The observer perceives the sound to have a grequency `(n + n_(1))` . If the sound velocity in air is `330 m//s` , then

Options

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

Answer

B

Explanation

`f' = f((v)/(v-v_(s) cos 90^(@))) = f = n`
`n+n_(1) = n rArr n_(1) = 0`