Question

A ray of light, incident on an equilateral prism `(μ_g = sqrt3)`moves parallel to the base line of the prism inside it. Find the angle of incidence for this ray.

Answer 1

It is given that the prism is equilateral in shape. So, all the angles are equal to 60°.

Thus, the angle of prism, A = 60°

The angle of refraction in case of a prism, `r =A/2 = 30°`

We can now apply Snell’s law

So,

μ_a sin i = μ_g sin r

Here, μ_a → refractive index of air, n₁ = 1

μ_g → refractive index of glass,`n_2 =sqrt3`

i → angle of  incidence

Thus,

`sin i = ((mug)/mu_a) sin r ((mug)/mu_a) sin 30° `

`sin i  = sqrt3/2`

So, the angle of incidence is

i =60°