Light is the external cause of sight. It produces the sensation of vision when it falls on the retina. Luminous objects like the sun emit their own light, while non-luminous objects like the moon are only visible because of light from luminous sources. Light propagates as electromagnetic waves and reflects off surfaces, with the angle of incidence equaling the angle of reflection.

1. Light Light is the external physical cause which produces the sensational of sight. When it falls on the retina of our eyes, it produces the sensation of vision and we can see the object

2. Luminous and non luminous object Luminous object Those object which themselves are a source of light i.e. they emit light, are called luminous bodies e.g. the sun, a burning candle, an electric bulb

3. Non luminous object Those bodies which do not emit light but are made visible by light falling from some luminous object on them, are called non-luminous bodies, for example, the moon, the earth, a table, a chair etc

4. (Properties of Light) We can see objects due to light but can not see light. Light propagate in form of electro -magnetic wave. In vacuum, speed of light is 3x10 8 m/s. On smooth surfaces it experience Reflection. When light travels from one medium to other medium, it experience Refraction. Home

5. When beam of light is incident on a plane surface, a part of it is returned into same medium. The return of light into same medium in this manner is called reflection of light . (Reflection of Light) Mirror

6. Laws of Reflection Angle of incident  i is equal to angle of reflection  r  i =  r 2. The incident ray, the reflected ray and the normal at the point of incident lie in the same plane.  i  r