Question

A ray of light travelling in the air falls on the surface of a plastic slab at an angle 53° ( $sin{53}^0$ = $\frac{4}{5}$) with the normal. The refractive index of plastic slab is 1.6. Calculate the angle of refraction.

Answer 1

Angle of incidence = ${53}^0$

Refractive index of glass = n = 1.6

Using snell's law:

$n=\frac{Sini}{Sinr}$

Sin r = $\frac{Sin{53}^0}{1.6}$

Sin r = $\frac{4}{5}$$\times$$\frac{1}{1.6}$

Sin r = $\frac{4}{5}$$\times$$\frac{10}{16}$

Sin r = $\frac{1}{2}$

$r={30}^0$

Angle of refraction, $r={30}^0$