1. The problem statement, all variables and given/known data In a Younf's double slit experiment , the intensity of light at the centre of fringe pattern is I. If one of the two identical slit is now covered , the intensity at the cnetre ANS is 0.25I. 2. Relevant equations 3. The attempt at a solution In my opinion, it should be 4I. because the light ray is now concentrated at smaller area, but i know that intensity = power /area . As the area is decreased is decreased , the intensity should increase , assuming the power is constant.