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प्रश्न
A man can read the number of a distant but clearly but he finds difficulty in reading a book.
What type of spectacle lens should he use to correct the defect?
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उत्तर
To correct his defect of vision, he should use convex lenses in his spectacles.
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संबंधित प्रश्न
What is myopia?
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?
What is the far point and near point of the human eye with normal vision?
Explain two possible reasons of myopia. How can it be corrected? Explain with a suitable diagram.
What is the scientific name of
long-sightedness?
Where is the near point of a person suffering from hypermetropia (or long-sightedness)?
Your friend can read a book perfectly well but cannot read the writing on blackboard unless she sits on the front row in class.
Is she short-sighted or long-sighted?
Name the following:
The photosensitive pigment present in the rods of the retina.
What is meant by optical illusion? Give one example.
Given below is a diagram depicting a defect of the human eye. Study the same and answer the question that follow:
Name the defect shown in the diagram.
A person is unable to see distinctly the objects closer than 1 m. Name the defect of vision he is suffering from. Draw ray diagrams to illustrate the cause of the defect and its correction by suitable lens.
List two causes of presbyopia. Draw labelled diagram of a lens used for the correction of this defect of vision.
Distinguish between the following pair of words:
Myopia and hypermetropia
Give Reason:
Deficiency of vitamin A causes night blindness.
Name the following:
The defect of the human eye caused due to the uneven surface of the cornea.
Differentiate the eye defects: Myopia and Hypermetropia
A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power:
Observe the figure and answer the following questions:
- Name the defect of vision represented in the above figure.
- State the reasons for this defect.
- How is it corrected?
- Draw the diagram to show the correction of this defect.
