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प्रश्न
Explain the functions of the following parts of the eye:
(i) cornea
(ii) iris
(iii) pupil
(iv) ciliary muscles
(v) eye-lens
उत्तर
Functions of the parts of the eye:
(i) Cornea: The front part of the eye that is made of a transparent substance and is convex in shape is called the cornea. The light from an object enters the eye through the cornea.
(ii) Iris: The iris is a flat, coloured and a ring-shaped membrane with a hole in the middle called the pupil. The iris regulates and controls the amount of light entering the eye by automatically adjusting the size of the pupil according to the intensity of light that the eye receives.
(iii) Pupil: The pupil is a hole in the middle of the iris and appears black because there is no light reflected from it. The pupil expands or contracts to regulate the amount of light entering the eye.
(iv) Ciliary muscles: The ciliary muscles contract or relax the eye lens and help in changing its focal length to focus the images of nearby or distant objects on the retina.
(v) Eye lens: The eye lens is a convex lens whose main function is to the converge the light rays from an object and form a real and inverted image of the object on the retina.
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संबंधित प्रश्न
Write the function of the following part of the human eye:- iris
Explain the following:
Mechanism of generation of light-induced impulse in the retina.
Name the part of the eye:
which changes the focal length of eye-lens.
A person walking in a dark corridor enters into a brightly lit room:
State the effect on the pupil of the eye.
When is a person said to have developed cataract in his eye? How is the vision of a person having cataract restored?
Out of animals of prey and predators, which have their eyes:
on the opposite sides of their head?
Name the following:
The part of the eye responsible for change in the size of the pupil.
Name the following:
The type of lens used for correcting myopia.
Which one of the following statements is NOT correct?
Match the following.
| Column - I | Column - II | ||
| 1 | Retina | a | Path way of light |
| 2 | Pupil | b | Far point comes closer |
| 3 | Ciliary muscles | c | near point moves away |
| 4 | Myopia | d | screen of the eye |
| 5 | Hypermetropia | e | Power of accomadation |
