Two sources of sound S1 and S2 vibrate at same frequency and are in phase (figure 16-E8). The intensity of sound detected at a point P as shown in the figure is I0. (a) If θ equals 45°, what will be the intensity of sound detected at this point if one of the Sources is switched off? (b) What will be the answer of the previous part if θ = 60o?


Given:
Resultant intensity at P = I0



The two sources of sound S1 and S2 vibrate with the same frequency and are in the same phase.



(a) When θ = 45°:
Path difference = S1P − S2P = 0


So, when the source is switched off, the intensity of sound at P is


Capture.PNG


(b) When the path difference is also. Similarly, it can be proved that the intensity at P is


When the source is switched off.


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