Reflection takes place when incoming light strikes the surface of a medium, obstructing some wavelengths which bounce back into the medium from which they originated.

  • The laws of reflection are as follows:
    • The incident ray, the reflected ray and the normal to the surface all lie in the same plane.
    • The angle the incident ray makes with the normal is equal to the angle which the reflected ray makes with the same normal.
    • The reflected ray and the incident ray are on the opposite sides of the normal.
  • Reflection takes place when light is neither absorbed by an opaque medium nor transmitted through a transparent medium.
  • As stated above, an important feature of reflection is that when light reflects off a surface, the angle of incidence of an incoming ray as it approaches the surface is equal to the angle of reflection.
  • If the reflecting surface is very smooth, the reflected light is called specular or regular reflection.
  • Specular reflection occurs when light waves reflect off a smooth surface such as a mirror. The arrangement of the waves remains the same and an image of the surfaces of objects that the light has already encountered become visible to an observer.
  • Diffuse reflection takes place when light reflects off a rough surface. In this case, scattering takes place and waves are reflected randomly in many different directions and so no image is produced.
  • Reflection off a surface can take place regardless of the optical density of the medium through which the incident light is propagating or of the medium it bounces off.