Task id13735

In Young's interference experiment, a polaroid P was introduced between the slit S and the slits S1 and S2 (figure), the main axes of which are parallel or perpendicular to the slits S1 and S2. How will the interference pattern on the screen change if slits S1 and S2 are covered with half-wavelength plates oriented mutually perpendicular to each other (parallel and perpendicular to the slits)? What happens if polaroid P is rotated 90°? What picture will be observed if you remove the Polaroid? Consider the same problem if instead