Class 10 notes of chapter the human eye in the the human eye, it is a natural optical instrument Which is used to see the objects by human beings it is like a camera, which has lens and screen system. Eye 1.Retina:- it is a light-sensitive screen inside the eye on which image is formed it contains rods and cones 2.cornea it acts like a lens which refracts the light entering the 3. aqueous humor:- it is fluid which fills the space between cornea and islands 4. Eye lens:- it is a convex lens made of transparent and flexible jelly-like material Its curvature can be adjusted with the help of ciliary muscles 5. pupil:- it is a hole in the middle of a virus through which light enters the eye It appears black because light falling on it goes into the eye and does not come back 6.ciliary muscles:- these are the muscles which are attached to eye lens and can modify the shape of eye lens which leads to the variation in focal lengths 7. iris:- it controls the amount of light entering the eye by changing the size of pupil 8.Optical nerve:- these are the nerves which take the image are the nerves which take the image to the brain in the form of electrical signals To accommodation power The ability of AI to change the focal length of islands with the help of ciliary muscles to get the clear view of nearby objects about 25 centimeters and far distant objects at infinity iii) color blindness some people do not possess some cone cells that respond to certain specific colors due to genetic disorder for myopia Shortsightedness, it is a kind of defect in human Eye, due to which a person can see near objects clearly, but he cannot see the distant objects clearly Myopia is due to is due to excessive curvature of cornea elongation Tropius long sightedness, it is a kind of defect in human eye, due to which a person can see distant objects properly, but cannot see the nearby objects clearly it happens due to I Decrease in power of eye lens ie increase in focal length of eye lens Six presbyopia, it is a kind of defect in human. Eye, which occurs due to aging it happens due to I decrease in flexibility of eye lens to gradual weakening of ciliary muscles An astigmatism it is a kind of defect in human eye due to which a person cannot see focus simultaneously horizontal and vertical lines both 8. cataract due to the membrane growth over islands the islands becomes hazy or even opaque This leads to decrease or loss of vision the problem is called cataract It can be corrected nine dispersion of white light by a glass prism The phenomenon of splitting of white light into its seven constituent colors when it passes through a glass prism is called dispersion of white light The various colors seen are violet indigo blue green yellow orange and red the sequence of colors remember as Vivier Ten composition of white light Consists of seven colors ie violet indigo blue green yellow orange and red 11. monochromatic light light consisting of single color or wavelength is called monochromatic light eg sodium light 12. Polychromatic light:- contain one or more than two colors, or wavelengths is called polychromatic light e.g. white light 13 recombination of white light Newton found that when an inverted prism be placed in the path of dispersed light then after passing through prism they recombined to form white light 14. formation of rainbow:- the water droplets act like small prisms They refract and disperse the incident sunlight, then reflected it internally and finally refracted again when it comes out of the raindrop Due to the dispersion of light and internal reflection different colors reach the observers. Eye 15. atmospheric refraction:- the refraction of light caused by the Earth’s atmosphere Having air layers of varying optical densities is called atmospheric refraction 16. why the duration of day becomes approximately four minutes shorter if there is no atmosphere on earth? Actual sunrise happens when it is below the horizon in the morning The rays of light from the Sun below the horizon reach our eyes because of refraction of light Similarly the Sun can be seen about few minutes in about few minutes after the actual sunset Thus the duration of daytime will increase by four minutes. 17 scattering of light:- according to Raley’s law of scattering the amount of scattered light a wavelength for So that the wavelength of violet blue an indigo is small its compared to the rest of the colors, so the sky appears blue in color Eighteen color of the Sun at sunrise and sunset At noon the light of Sun travels relatively shorter distance through Earth’s atmosphere thus appears White is only a little of blue and violet colors are scattered near the horizon Most of the blue light and shorter wavelengths are scattered and Sun appears red. Thanks! for Watching video please subscribe our channel don’t forget to like and share with your friends and classmates..