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प्रश्न
The defect of vision in which the eye-lens of a person gets progressively cloudy resulting in blurred vision is called:
(a) myopia
(b) presbyopia
(c) colourblindness
(d) cataract
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उत्तर
cataract
Cataract is the defect of vision because of which the eye lens gets progressively cloudy, resulting in blurred vision.
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संबंधित प्रश्न
Which defect of vision can be rectified:
by using a concave lens?
Which defect of vision can be rectified:
by using a convex lens?
What is the other name of old age hypermetropia?
Name any two defects of vision which can be corrected by using spectacles.
Name the body part with which the terms myopia and hypermetropia are connected.
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
What type of lenses-converging or diverging-would an optician prescribe for her?
A young man has to hold a book at arm's length to be able to read it clearly. The defect of vision is:
(a) astigmatism
(b) myopia
(c) presbyopia
(d) hypermetropia
A short-sighted person has a near point of 15 cm and a far point of 40 cm.
(a) Can he see clearly an object at a distance of:
(i) 5 cm?
(ii) 25 cm?
(iii) 50 cm?
(b) To see clearly an object at infinity, what kind of spectacle lenses does he need?
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 a young man
Name the following:
The photosensitive pigment present in the rods of the retina.
Enumerate the common defects of vision, their causes and the possible methods of correcting them.
Have a look at the posture of this girl who is reading a book and answer the questions which follow:
Name the problem she is facing.
What is Hypermetropia (far sightedness)?
List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision.
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
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.
What are the causes of ‘Myopia’?
Which of the following statement is correct?
Complete the following table by observing the given figures:
| Figure → |  |
 |
| Points ↓ | ||
| (a) Name of the defect | ______ | ______ |
| (b) Position of the image | ______ | ______ |
| (c) Lens used to correct the defect | ______ | ______ |
