The law of reflection states that when light falls upon a plane surface and is reflected, the angle of incidence is equal to the angle of reflection. This law is used when the incidence ray, the reflected ray and the normal all fall upon a plane area of incidence.
The behavior of light is known to be utterly predictable. When a light ray falls on a plane surface and is reflected, its behavior (the reflected ray) is the same as that of the incident ray. This is explained by the laws of reflection. The virtual ray that is perpendicular to the surface of reflection is known as the normal. The incidence ray represents the original ray, and it forms an angle of incidence as it meets the normal at the plane. Another element in reflection is the angle of reflection, which is the angle formed when the reflected ray diverges from the plane surface and the normal ray. The angle of incidence and the angle of reflection fall at opposite sides from the normal ray. The laws of reflection can also be applied in non-plane mirrors, in which case the normal is known to be the outward pointing perpendicular line from the tangent plane of the surface. This is the principle behind the ability of the human eye to see non-shiny objects.