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Science · 2023 · 3 marks
CBSE 2023 · Region 5 · Set 2 · Q29
Draw a labelled diagram of a common type of bifocal lens. State the function of each of its parts. Name the defect for the correction of which it is used and state its main cause.
Marking-scheme solution
The concave lens (upper portion of bifocal lens) facilitates distant vision.
The convex lens (lower portion of bifocal lens) facilitates near vision.
-Presbyopia
Diminishing flexibility of the eye lens.
Gradual weakening of ciliary muscles
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CBSE Class 10 Science past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.