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प्रश्न
Distinguish between the following pair of words:
Myopia and hypermetropia
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उत्तर
| Myopia | hypermetropia |
| (i) The image of distant object is produced in the front and not on the retina . | (i) The image is produced beyond the retina as the light rays are unable to converge on the retina. |
| (ii) It results from abnormally long eyeball . | (ii) It results from abnormally short eyeball. |
| (iii) The defect can be produced by high convexity of the lens . | (iii) The defect can be produced by low convexity of the lens . |
| (iv) It can be corrected by the use of spectacles having concave lens . | (iv) It can be corrected by the use of spectacles having convex lens . |
संबंधित प्रश्न
What is myopia?
Write the importance of ciliary muscles in the human eye. Name the defect of vision that arises due to gradual weakening of the ciliary muscles. What types of lenses are required by the person suffering from this defect to see the objects clearly?
Akshay, sitting in the last row in his class, could not see clearly the words write on the blackboard. When the teacher noticed it, he announced if any student sitting in the front row could volunteer to exchange his seat with Akshay. Salman immediately agreed to exchange his seat with Akshay. He could now see the words written on the blackboard clearly. The teacher thought it fit to send the message to Akshay’s parents advising them to get his eyesight checked.
In the context of the above event, answer the following questions:-
(a) Which defect of vision is Akshay suffering from? Which type of lens is used to correct this defect?
(b) State the values displayed by the teacher and Salman.
(c) In your opinion, in what way can Akshay express his gratitude towards the teacher and Salman?
List three common refractive defects of vision. Suggest the way of correcting these defects.
About 45 lac people in the developing countries are suffering from corneal blindness. About 30 lac children below the age of 12 years suffering from this defect can be cured by replacing the defective cornea with the cornea of a donated eye. How and why can students of your age involve themselves to create awareness about this fact among people?
Name the defect of vision in a person:
whose near point is more than 25 on away.
Explain the terms ‘adaptation’ and ‘accommodation’ with reference to the eye.
You do not enjoy watching a movie from a very short distance from the screen in a cinema hall. Why?
Draw a ray diagram to show how Hypermetropia is defect can be corrected using a lens.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow :
Name the type of lens used to correct this eye defect.
Draw ray diagram showing myopic eye.
