When light is incident on a surface, it partly goes back (reflected), partly
gets absorbed in the surface and the rest may transmit through it.
In practice, mirrors, formed by depositing a thin silver layer on one side
of the glass sheet are used to reflect the light.
The phenomenon of change in the path of light without
any change in the medium is termed as
reflection of light.
Angle of incidence: The angle which the incident ray makes with the normal at the
point of incidence is called the angle of incidence. It is generally denoted by
' i '.
Angle of reflection: The angle which the reflected ray makes with the normal at
the point of incidence is called the angle reflection. It is generally denoted by
' r '.
# that is angle of incidence is
equal to angle of reflection.
# Incident ray , reflected ray and normal to the mirror, all lie in the same plane.
Some Important Definations
(1)
Spherical Mirrors:A spherical mirror is a part of a hollow sphere or a spherical surface.
They are classified as concave or convex according to the reflecting surface being concaev or convex respectively
.
(2)
Radius of Curvature(R):Radius of curvature is the radius R of the sphere of which the mirror forms a part.
(3)
Pole or Vertex:The geometrical center of the spherical mirror is called the pole or vertex if the mirror.
(4)
Centre of curvature: The centre of curvature of spherical mirror is the centre of the sphere of which the
mirror forms a part. It is represented by C.
(5)
Principal axis: The line CP joinig the pole and the center of curvature of the spherical mirror
is called principal axis.
(6)
Focus (F): The point F is called the focus of the spherical mirror.
(7)
Focal Length(f): Focal length is the distance PF between the pole
and focus along the principal axis.
(8)
Aperture: The diameter of the spherical mirror is called the aperture
or linear aperture of the mirror.
Relation between radius of curvature (R) and focal length (f)
Top
The magnitude of the focal length in spherical mirrors is
half the radius of curvature,
