A Young's double slit experiment is performed using light of wavelength λ=5000A˚, which emerges in phase from two slits a distance d=3×10−7 m apart. A transparent sheet of thickness t=1.5×10−7 m is placed over one of the slits. The refractive index of the material of this sheet is μ=1.17. The central maximum of the interference pattern now appear at: ( D= distance between screen and slits)
(a) 0.085D
(b) D
(c) 1.2D
(d) 0.5D