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10.Light (Reflection and Refraction)
1. Ray of Light : A line drawn in the direction of propagation of light is called a ray of light.
2. Beam of Light : A group of rays of light emitted by a source of light is called a beam of
light. A light beam is of three types.
(i) Parallel beam : A group of light rays parallel to each other is known as parallel beam of
light. 7.
(ii) Divergent beam : A group of light rays spreading out from a source of light is called
divergent beam of light.
(iii) Convergent beam : A group of light rays meeting at a point is called convergent beam 8.
of light.
3. Reflection of Light : There are some surfaces which have ability to send the light back in
the same medium when light strikes it. This 9. phenomena of sending the light back in the same
medium by a surface is called reflection of light.
(i) The incident ray, the reflected ray and the normal at the point of incidence, all lie in a same
plane.
(ii) The angle of incidence is always equal to the angle of reflection, ∠i = ∠r.
4. Image : When light rays meet or appear to meet after reflection from a mirror,then it is
called an image.
1. Real Image : It is a kind of image which is formed by actual intersection of light rays after
reflection.
2. Virtual Image : It is a kind of image which is formed by producing the reflected rays
backward after reflection.
5. Plane Mirror : Plane mirror is a piece of glass whose one side is polished by using silver
paint, which is covered by a coating of red paint to protect the silver layer.
6. Spherical Mirrors : It is part of hollow glass sphere whose one surface is polished.
There are two types of spherical mirror.
(i) Concave Mirror : It is a spherical mirror whose outer surface is polished and inner or
concave side is reflecting surface.
(ii) Convex Mirror : It is a spherical mirror whose inner is polished and outer side or convex
side is the reflecting surface.
10.Light (Reflection and Refraction)
1. Ray of Light : A line drawn in the direction of propagation of light is called a ray of light.
2. Beam of Light : A group of rays of light emitted by a source of light is called a beam of
light. A light beam is of three types.
(i) Parallel beam : A group of light rays parallel to each other is known as parallel beam of
light. 7.
(ii) Divergent beam : A group of light rays spreading out from a source of light is called
divergent beam of light.
(iii) Convergent beam : A group of light rays meeting at a point is called convergent beam 8.
of light.
3. Reflection of Light : There are some surfaces which have ability to send the light back in
the same medium when light strikes it. This 9. phenomena of sending the light back in the same
medium by a surface is called reflection of light.
(i) The incident ray, the reflected ray and the normal at the point of incidence, all lie in a same
plane.
(ii) The angle of incidence is always equal to the angle of reflection, ∠i = ∠r.
4. Image : When light rays meet or appear to meet after reflection from a mirror,then it is
called an image.
1. Real Image : It is a kind of image which is formed by actual intersection of light rays after
reflection.
2. Virtual Image : It is a kind of image which is formed by producing the reflected rays
backward after reflection.
5. Plane Mirror : Plane mirror is a piece of glass whose one side is polished by using silver
paint, which is covered by a coating of red paint to protect the silver layer.
6. Spherical Mirrors : It is part of hollow glass sphere whose one surface is polished.
There are two types of spherical mirror.
(i) Concave Mirror : It is a spherical mirror whose outer surface is polished and inner or
concave side is reflecting surface.
(ii) Convex Mirror : It is a spherical mirror whose inner is polished and outer side or convex
side is the reflecting surface.
