Question

Consider the arrangement shown in figure (17-E7). By some mechanism, the separation between the slits S₃ and S₄ can be changed. The intensity is measured at the point P which is at the common perpendicular bisector

of S₁S₂ and S₃S₄. When z =Dλ/2d , the intensity measured at P is I. Find this intensity when z is equal to

(a) Dλ/d (b) 3Dλ/2d  and  (c) 2Dλ/d

Answer 1

So, the resultant intensity at P will be 2I.