( ii) Irregular or Diffused Reflection When a non-parallel beam of reflected light rays is obtained for a parallel beam of incident light rays after reflection from a surface, then such type of reflection is called irregular or diffused reflection.
Mirror
A smooth and highly polished reflecting surface is called a mirror.( i) Plane Mirror A highly polished plane surface is called a plane mirror. Different properties of image formed by plane mirror Size of image = Size of object Magnification == Unity
Distance of image == Distance of object A plane mirror may form a virtual as well as real image. A man may see his full image in a mirror of half height of man.
When two plane mirror are held at an angle θ, the number of images of an object placed between them is given as below
( a) n = [( 360 ° / θ) – 1 ], where 360 ° / θ is an integer.( b) n = integral part of 360 ° / θ, when 360 ° is not an integer.
[ A plane mirror may form a real image, when the pencil of light incident on the mirror is convergent. Children, during their play form an image of sun as wall by a strip of plane mirror.]
Kaleidoscope and periscope employ the principle of image formation by plane mirror.