refraction and eye

The Eye - Our eye is the most important natural optical instrument. The eye is nearly spherical in shape with a slight bulge in the front par..

. 'Iris' is a muscular diaphragm lying between the aqueous humor and the crystalline lens. Iris has an adjustable opening in the middle called the pupil of the eye. The pupil appears black because all the light entering is absorbed by the 'retina', which covers the inside of the rear part..

Atmospheric Refraction - Atmospheric refraction is the shift in apparent direction of a celestial object caused by the refraction of light rays as they pass through Earths atmosphere. The twinkling of stars and variation in size of the Sun are due to atmospheric r..

..

Introduction - You have studied in the previous chapter about refraction of light by lenses and also about the nature, position and relative size of images formed by lenses. How can these ideas help us in the study of the human eye? The human eye uses light and enables..

Conclusion - Thus, this chapter on refraction helps us understand many natural phenomena like the twinkling of stars, the sparkling of diamonds, mirage etc. It also throws light on the working of the human eye and the defects of visi..

Let us now perform an experiment and find out how light gets refracted when it is incident on a rectangular glass slab. Place a rectangular glass slab on a white sheet of paper fixed on a drawing board. Trace the boundary ABCD of the glass slab. Remove the glass slab. Draw an inc..

Let us now perform an experiment and find out how light gets refracted when it is incident on a rectangular glass slab. Place a rectangular glass slab on a white sheet of paper fixed on a drawing board. Trace the boundary ABCD of the glass slab. Remove the glass slab. Draw an inciden..

You must have seen some people holding books very close to their eyes. This is because they suffering from myopia (short sightedness). A myopic person cannot see distant objects clearly because the far point of his eye is less than infinity. Myopia is the defect of the eyeh..

Hypermetropia is caused due to the following reasons: Shortening of the eyeball, that is, the eyeball becomes smaller. Increase in focal length of the eye lens. Focussing of light rays in normal eye and long sighted eye Let us now see how this defect is rectified. A lo..