Answer:
Explanation:
wave length of sound waves = velocity / frequency
= 340 / 170
λ = 2 m.
When the position of man is exactly at the meddle point between the speakers , sound waves from the speakers reaching man are in same phases ( path difference is zero. ) so intensity of sound is maximum .
Now , the man starts moving towards one of the speakers , his distance from one speaker becomes closer than the other creating path difference for the sound waves reaching his ears.
If he walks a distance of .5 m towards one speaker , path difference created
= .5 x 2 = 1 m
So , path difference = λ /2 ,
there will be destructive interference so minimum sound will be heard there.
When he walks a distance of 1 m , path difference created = 2m
path difference = λ
so there is constructive interference and maximum sound will be heard there.
Again we he walks a distance of 1.5 m , path difference created = 3 m
path difference = 3 λ /2
So there will be destructive interference so minimum sound will be heard there.
In this way we see that man starts from a point of maximum sound intensity , reaches a point of minimum sound intensity , then reaches a point of maximum sound intensity . At last he reaches a position of minimum sound intensity.
