Question

A ray of light enters a rectangular glass slab at angle θ1 = 60° and emerges at an angle 90° as shown below. Refractive index of glass slab is

Answer 1

Thus the value of refractive index is  μ2 = √7 / 2

Explanation:

We are given that:

Angle θ1 = 60°

Angle θ2 = 90°

To Find: Refractive index

Solution:

Using Snell's law:

From Snell's law,

n1 sin θ₁  = n2 sin θ2

Now put the values.

1 × sin (60°) = μ2 sinθ2

√ 3 / 2 = μ2sinθ2 .........(1)

μ2sin(90° - θ2) = 1 × sin90°

μ2 Cosθ2 = 1 .........(2)

From equation (1) and (2)

tanθ₂ = √3/2

Sinθ2 = √3 / √7

From equation (1) we get:

√ 3 / 2 = μ2 × √3 /√7

μ2 = √7 / 2

Thus the value of refractive index is  μ2 = √7 / 2