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A. What is the… (Class 10 Science SQP 2024-25, Q31)

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ScienceCBSE Class 10 · Sample paper, session 2024-25 · 3 marks · Short answer

CBSE Class 10 Science sample paper 2024-25: question 31

From the official CBSE sample question paper for 2024-25, section C, question 31, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q31 · 3 marks · Short answerThe Human Eye and the Colourful World

A. What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of a person?
B. The diagram below shows a special case of an eye defect.
(i) What is the defect that is shown in the figure?
(ii) State one cause for such a defect?
(iii) Explain with reason if a concave lens can be used to correct the defect.

(For visually impaired students: A. What is the fundamental difference between hypermetropia and myopia in terms of the optical experience of a person? B. What are the causes of myopia in the human eye?)

Figure in the paper: Eye with lens; rays from a point N' converge to a point at the back (beyond the retina position); object points N and N' marked on the left on the axis. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

Ask yourself: which objects can each person see clearly, near or far?

Hint 2

In the figure, is the image formed in front of or behind the retina?

Hint 3

To bring the image forward onto the retina, should the rays be converged or diverged?

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. A. A person with hypermetropia sees distant objects clearly but has difficulty seeing near objects. A person with myopia sees near objects clearly, but distant objects appear blurred.

    1 mark

  2. B (i) The rays from the near point N' converge at a point behind the retina, so the defect is hypermetropia (long-sightedness).

    ½ mark

  3. (ii) Cause: the eyeball is too short, or the focal length of the eye lens is too long.

    ½ mark

  4. (iii) No. A concave lens diverges the rays and would push the image even farther behind the retina. A convex (converging) lens of suitable power is needed: it converges the rays so that the image forms exactly on the retina.

    1 mark

  5. (For visually impaired students) B. Causes of myopia: excessive curvature (high converging power) of the eye lens, and elongation of the eyeball.

Answer: A. Hypermetropia: near objects unclear; myopia: distant objects unclear. B (i) Hypermetropia; (ii) short eyeball / too long focal length; (iii) No, a convex lens is needed.

Where the marks are

  • Correct difference in optical experience (1 mark)
  • Identifies hypermetropia (0.5 mark)
  • One correct cause (0.5 mark)
  • Concave lens not suitable since it diverges rays; a convex lens is needed (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 2024-25: 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.