Question
Tue March 03, 2015 By: Bhargav Deshpande

DESCRIBE THE FUNCTION OF EYE WITH A NEAT LABELLED DIAGRAM.WHICH LENS IS USED TO CORRECT HYPERMETROPIA AND MYOPIC EYE?STATE THE LAWS OF REFLECTION

Expert Reply
Romal Bhansali
Tue March 03, 2015
The eye is an important sense organ and is roughly spherical in shape. 
 
 
 
1. Its transparent front part is called the cornea.
2. Behind the cornea, there is a dark muscular structure called the iris
3. The iris controls the amount of light entering the eye.
4. The pupil is a small opening in the iris whose size can be controlled.
5. Behind the pupil, the eye has a lens, which is thicker in the middle.
6. The lens converges light on the retina, which has a number of nerves.
7. The nerves carry the sensations to the brain through the optic nerve.
8. It contain two types of cells: 
a. Cones are sensitive to bright light and distinguish the colour of an object.
b. Rods are sensitive to dim light.
 
 
Myopic eye is corrected by using a concave lens.
Hypermetropic eye is corrected by using a convex lens.
 
The laws of refraction are:
1. The angle of incidence is equal to the angle of reflection.
 2. The incident ray, the reflected ray and the normal at the point of incidence, all lie in the same plane.
 
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