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प्रश्न
Name the defect of vision in a person:
whose near point is more than 25 on away.
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उत्तर
Hypermetropia is the defect of vision in a person whose near point is more than 25 cm away.
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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?
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
Name the defect of vision in a person:
whose far point is less than infinity
Name the defect of vision which makes the eye-lens cloudy resulting in blurred vision.
Name any two defects of vision which can be corrected by using spectacles.
What are the two most common defects of vision (or defects of eye)? How are they corrected?
Name the following:
The eye defect caused due to shortening of the eye ball from front to back.
What is Hypermetropia (far sightedness)?
Draw a ray diagram to show how Hypermetropia is defect can be corrected using a lens.
Write whether the following is true or false:
A convex lens is used for correcting myopia.
Rewrite the following table so as to match second and third column with first column.
|
Column I
|
Column II
|
Column III
|
|
(i) Myopia
|
Old age problem
|
Bifocal lens
|
|
(ii) Presbyopia
|
Nearsightedness
|
Concave lens.
|
The near point of the eye of a person is 50 cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25 cm from the eye?
Name an old age eye defect. Why is it caused?
Give Reason:
Deficiency of vitamin A causes night blindness.
What type of lens is used to correct Hypermetropia?
Nearsightedness: elongated eyeball : : farsightedness: _______
Assertion: Myopia is the defect of vision in which a person cannot see distant objects clearly.
Reason: This due to eye-ball being too short.
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.
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate lens.
