Question

What is the angle of incidence​

Answer 1

A ray of light hits a surface at a point. From that point the line straight up, at 90 degrees to the surface, is called the normal. The angle between the normal and the ray of light is called the angle of incidence.

Hope this helps u

Answer 2

the angle of incidence is the angle between a ray incident on a surface and the line perpendicular to the surface at the point of incidence, called the normal. The ray can be formed by any wave: optical, acoustic, microwave, X-ray and so on. In the figure below, the line representing a ray makes an angle θ with the normal (dotted line). The angle of incidence at which light is first totally internally reflected is known as the critical angle. The angle of reflection and angle of refraction are other angles related to beams.