The velocity of sound in air is `330 ms^(-1)`. To increase the apparent frequency of the sound by 50%, the source should move towards the stationary observer with a velocity equal to

Options

A. `330 ms^(-1)`
B. `220 ms^(-1)`
C. `165 ms^(-1)`
D. `110 ms^(-1)`

Answer

D

Explanation

`n' = n [(v)/(v - v_(s))]`
`1.5 n = n [(v)/(v - v_(s))]`
`v - v_(s) = (v)/(1.5)`
`v - (v)/(1.5) = v_(s)`
`(1.5v - v)/(1.5) = v_(s)`
`(0.5v)/(1.5) = v_(s)`
`v_(s) = (v)/(3) = (330)/(3) = 110 m//s`