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The above image shows… (Class 10 Science SQP 2025-26, Q35)

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ScienceCBSE Class 10 · Sample paper, session 2025-26 · 3 marks · Short answer

CBSE Class 10 Science sample paper 2025-26: question 35

From the official CBSE sample question paper for 2025-26, section C, question 35, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q35 · 3 marks · Short answerThe Human Eye and the Colourful World

The above image shows a corrective measure for a particular defect of vision.
(i) Identify the defect of vision and state what kind of lens is used to correct this deficiency.
(ii) Draw and label a ray diagram that shows the defect of vision in the above case before correction.

For visually impaired students:
(i) What is dispersion of light?
(ii) Explain the condition under which dispersion happens?
(iii) Give one reason that causes presbyopia.

Figure in the paper: An eye (large circle on the right with lens and retina) with a diverging (concave) lens placed in front of the eye. Rays from a point object on the left diverge and are shown as dashed lines extended backwards to a virtual image; after passing through the lens, the rays become parallel and enter the eye to focus on the retina. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2025-26.

Hints

Open one hint at a time and try again before the next.

Hint 1

Look at where the object is placed and where its rays appear to come from after passing through the correcting lens.

Hint 2

If a nearby object has to be made to appear farther away, the eye cannot focus close objects. Which defect is that?

Hint 3

In the defective eye, the image of a near object forms behind the retina. The fix is a lens that converges light.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (i) In the figure the object sits at the eye's near point (about 25 cm). After passing through the correcting lens, its rays appear to come from a virtual image N′ that is farther away. The eye can focus rays from N′ onto the retina. This is how NCERT shows the correction of a near point that has moved too far away, which happens in long-sightedness.

  2. Defect: hypermetropia (long-sightedness / far-sightedness). The person sees distant objects clearly but cannot see nearby objects clearly. The image of a near object would form behind the retina.

    ½ mark

  3. Correcting lens: a convex (converging) lens of suitable power. It adds converging power so the image of a near object forms on the retina.

    ½ mark

  4. (ii) Ray diagram of the defective eye, before correction. Draw these parts in order:

    • An eye (circle) with the eye lens and the retina.
    • Point N′, the near point of the defective eye, which lies farther than 25 cm.
    • Point N, the normal near point at 25 cm, placed closer to the eye than N′.
    • Rays from N′ passing through the eye lens and meeting on the retina.
    1 mark

  5. Then show the defect:

    • Rays from an object at N pass through the eye lens and would meet at a point behind the retina.
    • So the image of N is blurred.
    • Label N, N′, eye lens, retina and the image point behind the retina. Title the figure 'Hypermetropic eye'.
    1 mark

  6. For visually impaired students (alternative, 1 + 1 + 1 marks).

    (i) Dispersion is the splitting of white light into its seven component colours (VIBGYOR) when it passes through a prism. Each colour bends through a different angle, so the colours spread out into a spectrum.

  7. (ii) Condition for dispersion:

    • Light must pass from one medium into another (for example air into glass) and be refracted.
    • The medium must have a refractive index that is different for different colours (wavelengths), as glass and water do.
    • Then the colours travel at different speeds in the medium and bend by different amounts. Violet bends the most and red the least.

  8. (iii) Cause of presbyopia: with age, the ciliary muscles weaken and the eye lens loses its flexibility. The eye therefore loses its power of accommodation, the near point moves away, and nearby objects cannot be seen clearly.

Answer: (i) Hypermetropia; corrected by a convex (converging) lens. (ii) Ray diagram: rays from N (25 cm) meet behind the retina; the near point of the defective eye is N′, farther away. VI: (i) splitting of white light into its colours; (ii) refraction in a medium whose refractive index differs for different colours; (iii) weakening of ciliary muscles / loss of lens flexibility with age.

Where the marks are

  • Names the defect as hypermetropia (½ mark)
  • States that a convex (converging) lens corrects it (½ mark)
  • Diagram shows the eye with rays from N′ (shifted near point) focusing on the retina (1 mark)
  • Diagram shows rays from N (25 cm) meeting behind the retina, with correct labels (1 mark)
  • VI: correct definition of dispersion (1 mark); condition, i.e. refraction with a refractive index that depends on colour (1 mark); valid cause of presbyopia (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from The Human Eye and the Colourful World, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2025-26: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.