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प्रश्न
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उत्तर
One feels blinded for a short while on coming out of a dark room.This is called light adaptation of the eye.It is due to the constriction of the pupil to prevent the entry of light into the eye and pigment rhodopsin is bleached to reduce the sensitivity of the rods.
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संबंधित प्रश्न
List three common refractive defects of vision. Suggest the way of correcting these defects.
Name one defect of vision (or eye) which cannot be corrected by any type of spectacle lenses.
The picture given here shows a person wearing 'half-moon' spectacles. What sort of eye-defect do do you think he has? Why are these particular spectacles useful to him?
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.
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?
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?
Differentiate between:
Myopia and Hypermetropia.
Explain the Term: Hypermetropia
Draw ray diagram showing myopic eye.
When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?
