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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
What is the other name for
hypermetropia
Name the defect of vision which can be corrected by a diverging lens. Show clearly by a ray diagram how the lens corrects the defect.
The near point of a long-sighted person is 50 cm from the eye.
(a) Can she see clearly an object at:
(i) a distance of 20 cm?
(ii) at infinity?
State the main functions of the following:
Tears
Name the following:
The photosensitive pigment present in the rod cells of the retina.
Write whether the following is true or false:
A convex lens is used for correcting myopia.
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?
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
Correlate the given sequence:
Hypermetropia : Convex lens : ______ : Concave lens
Observe the following diagram and answer questions following it:
- Identify the defect of vision shown.
- List its two causes.
- Name the type of lens used for the correction of this defect.
