The angle between a ray that strikes a surface and the perpendicular to that surface at the point of contact is called the angle of incidence.

Here's a breakdown:

* Incident Ray: The ray of light that strikes the surface.

* Normal: The line perpendicular to the surface at the point where the incident ray strikes.

* Angle of Incidence: The angle between the incident ray and the normal.

It's important to note that the angle of incidence is always measured from the normal, not from the surface itself.