Laws of Reflection

 

    There are two laws of reflection

 

FIRST LAW OF REFLECTION

    According to the first law of reflection, the incident ray, the reflected ray and the normal at the point of incidence all lie in the same plane which is perpendicular to the plane of the reflecting surface (as shown in the figure below).

 

SECOND LAW OF REFLECTION

 

    According to the second law of reflection, the angle of incidence is always equal to the angle of reflection for small angles.

    i.e. Ði = Ðr

    Where

Ði = angle of incidence.

    Ðr = angle of reflection.

    The laws of reflection of light apply to all kinds of mirrors, plane mirrors as well as spherical mirrors.

Note: A ray of light which is incident normally on a reflecting surface (say a mirror), is reflected back along the same path because the angle of incidence as well as the angle of reflection for such a ray of light are zero. (i.e. Ði = Ðr = 0°.)