REFLECTION
Reflection of Light: The phenomenon of bouncing back of light into the same medium by the smooth surface is called reflection.
Incident light: Light which falls on the surface is called incident light.
Reflected light: Light which goes back after reflection is called reflected light.
The angle of incidence: The angle between the incident ray and the normal.
An angle of reflection: The angle between the reflected ray and the normal.
Mirror: The surface which can reflect the light is a mirror.
Plane Mirror: If the reflecting surface is a plane then the mirror is plane.
Spherical Mirror: If the reflecting surface is part of the hollow sphere then the mirror is a spherical mirror.
The spherical mirror is of two types:
Convex mirror: In this mirror reflecting surface is convex. It diverges the light so it is also called a diverging mirror.
Concave mirror: In this mirror reflecting surface is concave. It converges the light so it is also called converging mirror.
Parameters of Mirror:
Center of Curvature: The centre of hollow sphere of which mirror is a part.
The radius of curvature: The radius of hollow sphere of which mirror is a part.
Pole: The centre of mirror (middle point) is pole.
Principal axis: The line joining the pole and center of curvature is called principal axis.
Aperture: Size of mirror is called aperture of mirror.
Principal Focus: The point on the principal axis, where all the incident rays parallel to principal axis converge or diverge after reflection through mirror.
Focal Length: The distance between pole and focus point is focal length

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