The human eye and the colourful world · मानव नेत्र तथा रंगबिरंगा संसार
A free Physics lesson for Class 10 children.
Light enters the eye through the cornea and the pupil. The iris controls the size of the pupil.
The eye lens forms a real, inverted image on the retina, which sends signals to the brain through the optic nerve.
Ciliary muscles change the thickness of the lens to focus near and far objects. This is accommodation.
A person with myopia cannot see distant objects clearly. It is corrected with a concave lens.
A person with hypermetropia cannot see nearby objects clearly. It is corrected with a convex lens.
A prism splits white light into seven colours. This is dispersion.
Scattering of blue light by air makes the sky look blue. At sunrise and sunset the Sun looks red.
Stars twinkle because of atmospheric refraction.