A light ray from air is incident at on a rectangular glass slab of thickness and…
PHYSICS · Subjective · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A light ray from air is incident at 40∘ on a rectangular glass slab of thickness 3.0cm and refractive index 1.50 that is resting on the flat bottom of a tank filled with water (n=1.33). The ray refracts into the glass, enters the water and finally emerges into it.
(i) Find the angle the ray makes with the normal while travelling inside the glass.
(ii) Determine the angle with the normal of the ray inside the water.
(iii) Derive an expression for the lateral displacement d of the emergent ray in terms of slab thickness, angles involved and refractive indices, and hence calculate the numerical value of d.