Two cars A and B approach a stationary observer from opposite sides with the speed of 15m/s and 30 m/s respectively.The observer hears no beats. If the frequency of the horn of the car B is 504 Hz , the frequency of the horn of the car A will be :

Options

A. `440.5 Hz`
B. `298.2 Hz`
C. `529.2 Hz`
D. none of these

Answer

C

Explanation

`{:("Apparent frequency of car A",):}}={("Apparent frequency of car B",):}`
`(v)/(v-v_(s))xxv=(v)/(v-v_(s))xxv`
`(v)/(v-15)=(504)/(v-30)`
`v=(340-15)/(340-330)xx504`
`=529.2 Hz`.