Question

What is an emergent ray?

Answer 1

Hint: When an experiment is performed light rays are passed through a glass slab or prism. There are three types of rays which are mentioned in the practical: these are incident ray , emergent ray, reflected ray. Emergent rays can be clearly understood with the help of examples of light rays passing through the glass slab.

Complete answer:
For understanding emergent ray we will take a glass slab to understand how incident ray becomes reflected ray and then how reflected ray becomes emergent ray.When light ray passes through the glass slab the ray which passes is known as incident ray as shown in the diagram when light goes into the glass slab light ray tilts toward the normal it becomes reflected ray.
When a reflected ray moves out of a glass slab, the reflected ray becomes an emergent ray and it moves away from normal and is parallel to the incident ray.

This diagram represents how light ray moves in a glass slab and how an emergent ray is formed. Emergent ray is only formed when light passes two times when first light passes it becomes reflected ray and when second time when light passes it becomes emergent ray.

Note: Many of the students make the mistake about where to bend the light ray when it moves into the glass slab. It should be noted to avoid the confusion that when light moves from rarer medium to denser medium light bends toward the normal while if light moves from denser medium to rarer medium light ray moves away from normal.