In the shown YDSE, the upper slit is covered by a sheet of thickness t and refractive index 2μ, while the lower slit is covered by a sheet of thickness 2t and refractive index μ. Find the position y of the central maximum.

Question

G1 Physics · Accepted Answer

Upper sheet adds optical path (2μ-1)t; lower sheet adds (μ-1)2t. Their difference is t. To cancel it at the new central maximum, dy/D=t, hence y=tD/d with direction set by the greater optical delay. Option B.