Question

A ray of light is incident at the angle i on the surface of a glass slab. if its angle of refraction inside the glass block is r then find the relation between i and r assuming that light enters from air and emerges into air ​

Answer 1

Answer:

i = r

Explanation:

since, n1 and n2 are equal i.e.

n1 = n2 =1 (refractive index of air is 1)

hence, sini = sinr (Snell's law)

therefore, i=r

Answer 2

Answer:

Use Snell's law twice

Snell law

$\mu \sin( \theta) = constant$

$1. \sin(i) = \mu \: \sin(r) \\again \\ \mu \sin(r) = \: 1. \sin( \alpha )$

Eliminate mu from both equation

$\sin( \alpha ) = \sin(i) \times \frac{ \sin(r) }{ \sin(r) } \\ \sin( \alpha ) = \sin(i) \\ \alpha = i$