Our eyes alone cannot see any object. It is possible only when light reflected from an object enters our eyes. Light is the natural agent that stimulates sight and makes things visible. Light is reflected from all surfaces. Regular reflection takes place when light is incident on smooth, polished and regular surfaces. Diffused/irregular reflection takes place from rough surfaces. Bouncing back of light after striking the surface, in the same medium, is called reflection. The angle between the normal and the incident ray is called the angle of incidence. The angle between the normal and the reflected ray is called the angle of reflection.


(i) Regular Reflection: When a narrow beam of light strikes a mirror, the light will not reach your eye unless your eye is positioned at just the right place where the law of reflection is satisfied.

(ii) Diffused or Irregular Reflection: When light is incident upon a rough surface, it is reflected in many directions.


1. The angle of incidence is equal to the angle of reflection. 
2. Incident ray, reflected ray and the normal drawn at the point of incidence to the reflecting surface, lie in the same plane. 


1. Image formed in a plane mirror undergoes lateral inversion. 
2. Two mirrors inclined to each other give multiple images.
3. Beautiful patterns are formed in a kaleidoscope because of multiple reflections.
4. Sunlight, called white light, consists of seven colours.
5. Sunlight known as white light consists of seven different colours.
6. Splitting of light into its constituent colours is known as dispersion.
7. Prism can split light into its constituent colours.
8. Important parts of the eye are cornea, iris, pupil, lens, retina and optic nerve.
9. A normal eye can see nearby and distant objects clearly.
10. Visually challenged persons can read and write using Braille system.
11. Braille system has 63 dot patterns or characters. Each character represents a letter, a combination of letters, a common word or a grammatical sign.
12. Visually challenged persons develop their other senses more sharply to improve their interaction with their environment. 


(i) Cornea: Transparent bulge on the front surface of the eyeball which protects the eye and helps in refraction of light. 
(ii) Iris: Coloured diaphragm behind the cornea which controls the amount of light entering the eye. 
(iii) Pupil: Dark hole in the middle of iris through which light enters the eye. 
(iv) Eye lens: Transparent, crystalline structure behind pupil and iris. 
(v) Ciliary muscles: Hole the eye lens in position and control the focal length of the eye lens. 
(vi) Retina: Surface of the rear part of the eyeball where the light entering the eye is focused. 
(vii) Rods and Cones: Rod cells respond to the brightness of light while cone cells respond to colours. 
(viii) Blind spot: It is the least sensitive point where no rodsd and cones are present. 
(ix) The space between the cornea and the eye lens is filled with aqueous humour. 
(x) The space between the eye lens and the retina is filled with vitreous humour. 

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