Law of Reflection

Light travels in a straight line and may bounce back or pass through a medium where it travels. If light strikes through a transparent object, it passes through the object and continue traveling in straight line carrying energy. When it strikes through an opaque object, the transmission of light is interrupted and light may be absorbed and give off its energy on the medium which makes it heat up. Sometimes, light bounces off as it strikes through an object. This bouncing back of light is called as the reflection of light. There are two types of reflection depending on the surface where the light strikes. Specular or regular reflection is the reflection on smooth surface. Diffuse reflection is the reflection in rough surfaces. These two all obey the law of reflection but in the diffuse reflection, the angle of incidence and angle of reflection varies from point to point.

In describing the reflection of light, we must define first the following terms used in the discussion:

Incident ray is the ray approaching the surface. The ray reflected by the surface is the reflected ray. The point of incidence is the point where the incident ray strikes on the surface. A line is drawn at right angle to the surface at the point of incidence which is called the normal. The angle of incidence is the angle between the incident ray and the normal and the angle between the reflected ray and the normal is called as the angle of reflection.

The Laws of Reflection are stated as follows:

  1. The angle of incidence is equal to the angle of reflection.
  2. The incident ray, reflected ray, and the normal all lie on the same plane.