CBSE 2025 · Region 4 · Set 1 · Q25 · 2 marks
Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle through which the emergent ray bends from the direction of the incident ray and also name it.Name the type of lenses required by the persons for the correction of their defect of vision called presbyopia. Write the structure of the lenses commonly used for the correction of this defect giving reason for such designs.
Draw a ray diagram to show the refraction of a ray of light passing through an equilateral glass prism. Mark the angle through which the emergent ray bends from the direction of the incident ray and also name it.
Name the type of lenses required by the persons for the correction of their defect of vision called presbyopia. Write the structure of the lenses commonly used for the correction of this defect giving reason for such designs.
Marking-scheme solution
(A) 
(one mark for diagram and \(\displaystyle \frac{1}{2}\) for labelling.)
(one mark for diagram and \(\displaystyle \frac{1}{2}\) for labelling.)Angle of deviation
I.
Bi-focal lens.
Bi-focal lens having upper portion consists of a concave lens and lower portion consists convex lens. /
to facilitate the distant and near vision respectively.
II. convex lens. Convex lens is thickened at the middle as compared to edges /
to facilitate the near vision.
(either of I or II)
The Human Eye and the Colourful WorldDefects of Vision and their CorrectionApplyvery_short_answermedium
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CBSE Class 10 Science past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.