# Angle of Incidence

## Angle of Incidence

The Angle of Incidence can be defined as the angle with which a light ray strikes a reflecting surface. But the angle of strike is measured as the angle between the ray and the normal to the surface at the point of incidence of the ray. It has a relation with the angle of reflection and also with the type of reflecting surface. The ray I from a light source strikes the mirror MM’ at point O, is called as Incident ray. ON is the perpendicular to the MM’ at O which is also called the normal to the mirror at O. The angle x made by the ray I, with the normal ON is called as Angle of Incidence.

The Incident ray, is reflected by the mirror when it strikes the mirror at O and the ray after reflection R is called as Reflected ray. The angle y made by the reflected ray with the same ray is called as Angle of Reflection.

The angle of incidence and the angle of reflection is always equal and they are both on the same plane along with the normal.

Relation to Refraction: When light passes from one medium to another with different densities, its path gets deviated. This phenomenon is called the Refraction of light. Like reflection, there are similar components in refraction too:

• Incident Ray,
• Refracted Ray,
• Normal,
• Point of Incidence.