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प्रश्न
Give Reason:
When you enter into a dark room from bright because of sunlight, you can not see things for a few seconds.
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उत्तर
In bright light the visual purple or rhodopsin pigment is destroyed and the diameter of the pupil is reduced to allow the entry of less light.
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संबंधित प्रश्न
About 45 lac people in the developing countries are suffering from corneal blindness. About 30 lac children below the age of 12 years suffering from this defect can be cured by replacing the defective cornea with the cornea of a donated eye. How and why can students of your age involve themselves to create awareness about this fact among people?
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision?
What is the scientific name of
long-sightedness?
Name one defect of vision (or eye) which cannot be corrected by any type of spectacle lenses.
The defect of vision which cannot be corrected by using spectacles is:
(a) myopia
(b) presbyopia
(c) cataract
(d) hypermetropia
When do we consider a student sitting in the class to be myopic? List two causes of this defect. Explain using a ray diagram how this defect of eye can be corrected.
Name the following:
The photosensitive pigment present in the rod cells of the retina.
Explain the Term: Hypermetropia
Study the following diagram carefully and then answer the questions that follow. The diagram is depicting a defect of the human eye :
(i) Identify the defect shown in the diagram.
(ii) Give two possible reasons for the above defect.
Nearsightedness : concave lens : : farsightedness : _______
