Answer:
Angle of incidence
Explanation:
The diagram shows the reflection of a light ray.
When a light ray undergoes reflection:
- The incident ray, the reflected ray and the normal to the surface all lie in the same plane
- The angle of reflection is equal to the angle of incidence
The two angles are defined as follows:
- The angle of incidence is the angle between the incident ray and the normal to the surface (1)
- The angle of reflection is the angle between the reflected ray and the normal to the surface
In the picture, we see that the angle marked with X corresponds to the angle defined in (1), so it is the angle of incidence.
