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प्रश्न
Name an old age eye defect. Why is it caused?
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उत्तर १
Presbyopia is an age-old eye defect. In this condition, the lens loses flexibility resulting in far-sightedness.
Cataract is also very common in old people, the cornea becomes opaque and the vision is cut down even to blindness.
उत्तर २
Hypermetropia. It is caused due to flattening of the eye lens (Also presbyopia in which lens looses flexibility).
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संबंधित प्रश्न
Where is the near point of a person suffering from hypermetropia (or long-sightedness)?
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
From which defect of the eye is he suffering?
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
What type of spectacle lens should he use to correct the defect?
Name the defect of vision which can be corrected by a diverging lens. Show clearly by a ray diagram how the lens corrects the defect.
A person can read a book clearly only if he holds it at an arm's length from him. Name the defect of vision:
if the person is an old man
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
Anuja cannot see the blackboard writing but she can see nearby things.
(a) What is the eye defect she is suffering from?
(b) State the possible reason for her defect.
(c) How is it corrected
Give Reason:
Why do we see clearly in the central region of the retina?
Differentiate between:
Myopia and Hypermetropia.
Assertion: Concave mirrors are used as reflectors in torches, vehicle head lights and in search lights.
Reason: When an object is placed beyond the center of curvature of a concave mirror, the image formed is real and inverted.
