Consider the huge glass slab kept horizontally on top of a point source of light ‘S’ as shown in the diagram. The slab is of thickness t = 3 m and length ‘2 λ ’ = 9 m. A person whose eyes can be taken at height ‘h’ above the upper face of glass slab walks over the slab from one edge ‘A’ to the point ‘B’ right on top of the point source ‘S’. When at ‘A’ and observing ‘S’ the line of vision of the person makes ‘ θ ’ (= 60º) with the normal to the slab. Refractive index of the slab is µ( ). Find