Question

A small ink dot on a paper is viewed through a glass slab of thickness `10 cm` , and refractive index `1.5`. By what distance would the dot appear to be raised ?

Answer 1

Here, real thickness of glass slab, `x = 10 cm , mu = 1.5`
If apparent thickness of glass slab is `y`, then from `mu = (x)/(y)`
`y = (x)/(mu) = (10)/(1.5) = 6.67 cm`
Distance through which the dot appears to be raised `= x - y = 10 - 6.67 = 3.33 cm`.