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प्रश्न
Explain the Term: Cataract
उत्तर
Cataract: It is a condition in which the lens turns opaque and the vision is cut down even to total blindness. It can be corrected by surgically removing the lens and by using spectacles with highly convex lense.
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संबंधित प्रश्न
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
What is the scientific name of
short-sightedness
Where is the near point of a person suffering from hypermetropia (or long-sightedness)?
What are the two most common defects of vision (or defects of eye)? How are they corrected?
State the main functions of the following:
Tears
Select the odd one in the following series:
Endolymph, Tympanic membrane, Semi-circular canal, Blind spot.
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What are the two conditions shown in sections A and B of the eye as applicable to her?
Have a look at the posture of this woman who is reading a book and answer the questions which follow:
What kind of looking glasses she needs?
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.
|
Solve the following question:
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?
Give Reason:
Older people require glasses to read and write.
Differentiate between:
Myopia and Hypermetropia.
Explain the Term: Hypermetropia
What type of lens is used to correct Astigmatism?
With respect to human eye explain:
(i) How is the image formed on the retina?
(ii) How is the amount of light entering the eye-controlled?
(iii) What type of lens is used for the correction of ‘Long sight’ defect?
(iv) With the help of a ray, diagram show the defect of the eye and then its correction after the use of a lens.
Due to elongation of _______ and increase in curvature of the eye lens, a person cannot see distant objects clearly.
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Name the following:
Two kinds of accomodations.
