Question

A light beam passes through a thick slab of material whose index of refraction is $n_2$. Show that the emerging beam is parallel to the incident beam.

Short answer

Hence,$\theta$ is the angle of refraction of the emerging beam.

Step-by-step solution

Step 1. Given Information  

A light beam passes through a thick slab of material whose index of refraction is $n_2$.

We have to show that the emerging beam is parallel to the incident beam.

Step 2. A light beam passes through a thick slab of material whose index of refraction is n2.

If $\theta$is the original angle of incidence and $\varphi$is the angle of refraction, then$\frac{\sin \theta }{\sin \varphi }=n_2$.

Step 3. The angle of incidence of the emerging beam is also ϕ and the index of refraction is 1n2.

Thus$\theta$is the angle of refraction of the emerging beam.