Question

A ray of light enters a glass slab $ABCD$ ac shown in Fig. and strikes at the centre $O$ of the circular part $AC$ of the slab. The critical angle of glass is ${42^ \circ }$. Complete the path of the ray till it emerges out from the slab. Mark the angles in the diagram whenever necessary.

Answer 1

Hint:In order to answer this question let us first understand about the ray of light. A ray of light is light that travels in a straight line in one direction. A beam of light is a collection of light rays emitted from a single source.

Complete answer:
Let us first get some idea about the refraction. Light refraction is one of the most well-known phenomena, but other waves, such as sound and water waves, can also refract. We may use optical equipment like magnifying glasses, lenses, and prisms because of refraction. We may also focus light on our retina because of refraction of light.

The greatest angle at which a beam of light travelling through one transparent media can strike the border between that medium and a second of lower refractive index without being completely reflected within the first medium is known as the critical angle in optics.

Because the beam is incident on the glass at its critical angle, the angle of refraction will be ${90^ \circ }$.

Note: Snell's law can be used to compute the critical angle by setting the refraction angle to\[{90^ \circ }\]. Portions of the incident light will be transmitted and part will be reflected at any angle of incidence less than the critical angle.Snell’s law gives the degree of refraction and relation between the angle of incidence, the angle of refraction and refractive indices of a given pair of media.