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प्रश्न
Explain the Term: Hypermetropia
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उत्तर
With age, the elasticity of the lens decreases, and the individual becomes long-sighted and is called Hypermetropia In this condition, the diameter of the eyeball from front to back is too short. The clear image falls beyond the retina and the eye sees a blurred image. Hypermetropia may be corrected by the use of a biconvex lens.
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संबंधित प्रश्न
The far point of a myopic person is 80 cm in front of the eye. What is the nature and power of the lens required to correct the problem?
What is the far point of a person suffering from myopia (or short-sightedness)?
A person cannot read newspaper placed nearer than 50 cm from his eyes. Name the defect of vision he is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Draw a ray diagram to show how this defect may be corrected using a lens of appropriate focal length.
State one role of ciliary muscles in the human eye.
A person is unable to see objects distinctly placed within 50 cm from his eyes.
(a) Name the defect of vision the person is suffering from and list its two possible causes.
(b) Draw a ray diagram to show the defect in the above case.
(c) Mention the type of lens used by him for the correction of the defect and calculate its power. Assume that the near point for the normal eye is 25 cm.
(d) Draw a labeled diagram for the correction of the defect in the above case.
Name the common defects of the eye.
Give Reason:
Why do we see clearly in the central region of the retina?
Nearsightedness : concave lens : : farsightedness : _______
Myopia may arise due to ____________.
A person needs a lens of power –4.5 D for correction of her vision.
- What kind of defect in vision is she suffering from?
- What is the focal length of the corrective lens?
- What is the nature of the corrective lens?
