Question

A dot on a paper appears to be raised by 4 cm when viewed normally through a glass slab placed on it. Calculate the thickness of the glass slab if it's refractive index is 1.5

Answer 1

We know that the Refractive index = real depth/apparent depth = 1.5

Let the thickness of  the glass slab be x

real depth is x cm.

so apparent depth = (x-4) cm.

real depth = 1.5 * apparent depth

x = 1.5*(x-4)

0.5x = 6

x = 6/0.5 = 12

So, Thickness of glass is 12 cm