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प्रश्न
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.
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उत्तर
(i) Light from the source when reaching the eye, it gets converted by the lens and an inverted image is formed on the retina.
(ii) The amount of light entering the eye can be controlled by dilating or constricting the pupil.
(iii) A biconcave lens is used to correct long-sightedness.
(iv)
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संबंधित प्रश्न
A person suffering from the eye-defect myopia (short-sightedness) can see clearly only up to a distance of 2 metres. What is the nature and power of lens required to rectify this defect?
What eye defect is hypermetropia? Describe with a ray diagram how this defect of vision can be corrected by using an appropriate lens.
The diagram alongside represents a section of a mammalian eye.
(i) Label the parts 1 to 5 of the diagram.
(ii) State the function of the parts labelled 4 and 5.
(iii) With the help of a diagram show the short sightedness.
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:
Deficiency of vitamin A causes night blindness.
Explain the Term: Presbyopia
Nearsightedness : concave lens : : farsightedness : _______
Write scientific reason.
Nearsightedness, this defect can be corrected by using spectacles with concave lens.
Name the following:
Two kinds of accomodations.
Given alongside is a diagram depicting a defect of the human eye. Study the same and answer the questions that follow:
 |
- Name the defect shown in the diagram.
- Give two possible reasons for this defect.
- Name the parts labelled 1 to 4.
- Name the type of lens used to correct this eye defect.
- Draw a labelled diagram to show how the above mentioned defect is rectified using the lens named above.
