Question

A cube of edge 6 cm is placed over a printed page. At what distance from the top surface of cube will the letters appear when seen from above?
Refractive index of glass is 1.5

Answer 1

Real depth = 6cm 
Refractive index = 1.5 Apparent depth = Real depth / Refractive index 
Apparent depth = 6 / 1.5 = 4cm 
Hence, the letters will appear at a distance of 4cm from the top surface of the cube.