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प्रश्न
the biological/technical terms for the lens of eye losing flexibility resulting in a kind of long-sightedness in middle aged people.
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उत्तर
The lens of eye losing flexibility resulting in kind of long-sightedness in middle aged people – Presbyopia
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संबंधित प्रश्न
Given below is a diagram showing a defect of human eye. Study it and answer the following questions.
(i) Name the defect shown in the figure.
(ii) Give reason for this defect of eye in human being.
(iii) Name the type of lens used to correct the eye defect.
In a Std. X class out of 40 students 10 students use spectacles, 2 students have positive power and 8 students have negative power of lenses in their spectacles.
Answer the following questions:
(1) What does the negative power indicate?
(2) What does the positive power indicate?
(3) Generally which type of spectacles do most of the students use?
(4) What defect of eyesight do most of the students suffer from?
(5) Give two possible reasons for the above defect.
Given below is a diagram depicting a defect of the human eye? Study the same and answer the question that follow :
Name the type of lens used to correct this eye defect.
Name an old age eye defect. Why is it caused?
Give Reason:
Why do we see clearly in the central region of the retina?
Explain the Term: Hypermetropia
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?
State reasons for Myopia. With the help of ray diagrams, show the:
- image formation by a myopic eye, and
- correction of myopia using an appropriate 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.
