Two small loudspeakers `A , B` ( `1m` apart) are connected to the same oscillator so that both emit sound waves of frequency `1700 Hz` in phase . `A` sensitive detector , detects a maximum wave at `P` on the perpendicular bisector `MP of AB` and another maximum wave when it first reaches a point `Q` directly opposite to `B`. Calculate the speed `c` of the sound waves in air .

Explanation

`AQ - BQ = lambda `for constructive interference of waves at Q
or `sqrt(1.00^(2) + 2.40^(2)) - 2.40 = lambda` or `labmbda = 0.2 m`
Thus we get `v = nlambda`
`v = 1700 xx 0.2` = `340 m/s`.