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प्रश्न
How does the eye regulate the amount of light that falls on the retina?
उत्तर
Pupil is the small aperture in the iris that regulates the amount of light entering the eye. Cornea, aqueous humour, lens, and vitreous humour act together and refract light rays, focussing them onto the photoreceptor cells of the retina
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संबंधित प्रश्न
The optical prescription for a pair of spectacles is :
Right eye : −3.50 D
Left eye : −4.00 D
Are these lenses thinner at the middle or at the edges?
What change is made in the eye to enable it to focus on objects situated at different distances? Illustrate your answer with the help of diagrams.
Name the cells on the retina of an eye which are sensitive to (i) bright light (ii) dim light (iii) sensation of colour.
How does the eye adjust itself to deal with light of varying intensity?
If you walk from a dark room into sunlight and back again into dark room, how would your pupils alter in size? What makes this happen?
The human eye forms the image of an object at its ______.
Fill in the following blank with suitable word:
Having two eyes gives a ................field of view.
Fill in the following blank with suitable word:
Having two eyes enables us to judge.................more accurately.
Among animals, the predators (like lions) have their eyes facing forward at the front of their heads, whereas the animals of prey (like rabbit) usually have eyes at the sides of their head. Why is this so?
Choose the correct answer :
The rods and cones of a vertebrate retina function is to _________
Answer the following question.
Write the structure of eye lens and state the role of ciliary muscles in the human eye.
State the Location:
Iris
The pigmented circular area seen in front of the eye:
The change in the focal length of an eye lens in human beings is caused by the action of ______.
With neat, labeled diagram describe the structure of retina of eye.
Match the following:
| Column - I | Column - II |
| 1. Retina | a. Pathway 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 | f. Power of accommodation |
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 |
State the functions of the following:
Iris
Name the following:
The layer of the wall of the eye-ball that corresponds to the black lining of the box of a camera
The layer in the eye where sensory cells (rods and cones) are located ______.
