Question

(a) Write the functions of each of the following parts of the human eye:
(i) Cornea
(ii) Iris
(iii) Crystalline (Eye) lens
(iv) Ciliary muscles
(v) Retina
(b) A person is unable to see distinctly the objects closer than 1 m. Name the defect of vision he is suffering from. Draw ray diagrams to illustrate the cause of the defect and its correction by suitable lens

Answer 1

Heya mate here is your answer.....
1)Cornea is a thin and transparent cover by which maximum refraction of light rays entering the eye.
2) Iris is a dark fleshy screen, colour of Iris is different for different people.
3) Ciliary muscles hold the eye lens in its position and change the shape of eye lens
4) Retina is a light sensitive screen


Hope it helps you.....

Answer 2

(I). Cornea is the outermost lens of eye. It contributes about 65-75% of the total focusing of eye.

(II). Iris controls the size of the pupil.

(III). It is a lens made of natural fibres. It contracts and expands with the help of ciliary muscles.

(IV). It controls the focal length by adjusting the crystalline lens.

(V). Retina is a light sensitive screen on which the images of objects forms.

b. He is suffering from myopia or short sightedness....

HOPE THIZ HELPZ........

ALSO DONT FORGET TO HELP ME PLZ....☺