TYPES 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.
TWO LAWS OF REFLECTION
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.
POINTS TO REMEMBER
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.
PARTS OF HUMAN EYE
(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.