For a ray of light undergoing refraction through a triangular glass prism the angle of deviations is the angle between:

Correct option is B

The correct answer is (b) The incident ray and the emergent ray.
· The angle of deviation in the refraction of light through a triangular prism is defined as the angle between the incident ray and the emergent ray after passing through the prism.
Key Points:
1. Incident Ray: The ray of light entering the prism.
2. Refracted Ray: The ray of light bending inside the prism.
3. Emergent Ray: The ray of light exiting the prism.
4. Angle of Deviation: The angle between the original path of the incident ray and the final path of the emergent ray.
This deviation occurs because the light bends twice—once upon entering the prism and once upon leaving it.
Clarifications for Other Options:
· The incident ray and the normal at the point of incidence: Describes the angle of incidence, not deviation.
· The incident ray and the refracted ray: Refers to the angle of refraction at the first interface.
· The refracted ray and the emergent ray: Describes the internal bending, not the overall deviation.