The correct Answer is Angle of deviation
Explanation
Refraction is the phenomenon of bending of light as it passes from one medium to another. When light passes through a glass prism, it undergoes two refractions: one at the interface where it enters the prism and another at the interface where it exits the prism. The path of the light ray changes direction, and the overall change in direction is quantified by a specific angle.
Statement-wise Analysis
- Angle of dispersion - Incorrect
The angle of dispersion refers to the angular separation between two specific colors (e.g., red and violet) of light after passing through a prism. It quantifies the extent to which different wavelengths of light are separated due to their different refractive indices in the prism material. It is not the angle between the incident and emergent rays.
- Angle of deviation - Correct
The angle of deviation is defined as the angle between the direction of the incident ray and the direction of the emergent ray. It represents the total change in the direction of the light ray as it passes through the prism.
- Angle of emergence - Incorrect
The angle of emergence is the angle that the emergent ray makes with the normal to the second refracting surface (the surface from which the light exits the prism). It is one of the angles involved in the refraction process but not the angle between the incident and emergent rays.
- Angle of incidence - Incorrect
The angle of incidence is the angle that the incident ray makes with the normal to the first refracting surface (the surface where the light enters the prism). It describes the initial direction of the light ray relative to the prism's surface, not the overall change in direction.
Key Takeaway: The angle of deviation quantifies the total change in direction of a light ray as it passes through a prism, measured between the incident and emergent rays.