Two sound sources are moving in opposite directions with velocities ` v_(1) and v_(2) ( v_(1) gt v_(2))` . Both are moving away from a stationary observer. The frequency of both the sources is 900 Hz. What is the value of ` v_(1) - v_(2)` so that the beat frequency aboserved by the observer is 6 Hz. speed of sound v= 300 m/s given ,that `v_(1) and v_(2) lt lt v `

Options

A. `1(m)/(s)`
B. `2(m)/(s)`
C. `3(m)/(s)`
D. `4(m)/(s)`

Answer

B

Explanation

`f_1=900((300)/(300+v_1))`
`cong900(1+(v_1)/(300))^-1`
`=900-3v_1`
similarly,
`f_2=900((300)/(300+v_2))=900-3v_s`
`f_2-f_1=6`
`3(v_1-v_2)=6`
`3(v_1-v_2)=6`
or `v_1-v_2=2(m)/(s)`