An engine driver moving towards a wall with velocity of `50 ms^(-1)` emits a note of frequnecy `1.2 kHz`. The frequency of note after reflection from the wall as heard by the engine driver when speed of sound in air is `350 ms^(-1)` is :

Options

A. 2.4 kHz
B. 0.24 kHz
C. 1.6 kHz
D. 1.2 kHz

Answer

C

Explanation

Frequency heard by the engine driver is
`n'=((v+v_(o))/(v-v_(s)))n`
`=((350+50)/(350-50))xx1.2=1.6kHz`