( 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 .