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प्रश्न
Differentiate between:
Short-sightedness and Long-sightedness.
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उत्तर
| Short-Sightedness | Long-Sightedness |
| (i) The inability of the eye lens to focus images of distant objects on the retina; so the images fall in front of the retina. | The inability of the eye lens to focus near object images on the retina; so the images fall beyond the retina. |
| (ii) It is corrected by using glasses of a concave lens. | It is corrected by using glasses of a convex lenses. |
APPEARS IN
संबंधित प्रश्न
List three common refractive defects of vision. Suggest the way of correcting these defects.
Which defect of vision can be rectified:
by using a concave lens?
The near-point of a person suffering from hypermetropia is at 50 cm from his eye. What is the nature and power of the lens needed to correct this defect? (Assume that the near-point of the normal eye is 25 cm).
Differentiate between members of the following pair with reference to what is asked in the bracket.
Rods and cones (sensitivity).
A student cannot see a chart hanging on a wall placed at a distance of 3 m from him. Name the defect of vision he is suffering from. How can it be corrected? Draw ray diagrams for the (i) defect of vision and also (ii) for its correction.
An old man cannot see objects closer than 1 m from the eye clearly. Name the defect of vision he is suffering from. How can it be corrected? Draw ray diagram for the (i) defect of vision and also (ii) for its correction.
Observer the following diagram and answer the questions.
a) Which eye defect is shown in this diagram?
b) What are the possible reasons for this eye defect?
c) How this defect is corrected, write it in brief?
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.
Draw a neat labeled diagram to show how hypermetropia can be rectified.
Name the following:
The defect of the human eye caused due to the uneven surface of the cornea.
