JEE Mains Model Paper 9

Monochromatic light of wavelength λ emerging from slit S illuminates slits S1 and S2 which are placedwith respect to S as shown in fig. The distances x and D are large compared to the separation d betweenthe slits. If x = D/2, the minimum value of d so that there is a dark fringe at the centre P of the screenis