What is an incident ray in optics?

In the context of optics, an incident ray refers specifically to the incoming ray of light that strikes a surface. This concept is crucial in understanding how light interacts with different materials, as it sets the stage for subsequent phenomena such as reflection, refraction, and absorption. When light encounters a surface, the angle at which it hits is termed the angle of incidence, which is fundamental in predicting how the light will behave upon contact with the surface.

The classification of the incident ray as the incoming ray is particularly important. It helps students grasp why the behavior of light changes depending on the characteristics of the surface it interacts with and the angle at which it strikes. This understanding is foundational for topics such as the laws of reflection and refraction, further emphasizing the relevance of incident rays in various optical applications.