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Define the term power of… (Class 10 Science 2024, Q31)

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ScienceCBSE Class 10 · Board exam 2024, set 31/4/1 · 3 marks · Short answer

CBSE Class 10 Science 2024: question 31

Set in the CBSE Class 10 board exam of 2024, paper 31/4/1, 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

Define the term power of accommodation of human eye. What happens to the image distance in the eye when we increase the distance of an object from the eye ? Name and explain the role of the part of human eye responsible for it in this case.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/4/1.

Hints

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

Hint 1

The distance between the lens and the retina cannot change.

Hint 2

Which muscles change the shape of the lens, and what happens to them for distant objects?

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. Power of accommodation is the ability of the eye lens to adjust its focal length so that both near and distant objects can be seen clearly.

    1 mark

  2. The image distance remains unchanged. The image is always formed on the retina, at a fixed distance from the lens.

    1 mark

  3. The part responsible is the ciliary muscles.

    ½ mark

  4. When the object is moved farther away, the ciliary muscles relax. The eye lens becomes thinner and its focal length increases, so the image still forms on the retina.

    ½ mark

Answer: Power of accommodation is the ability of the eye lens to adjust its focal length. The image distance remains the same. The ciliary muscles relax, making the lens thin and increasing its focal length.

Where the marks are

  • Definition of power of accommodation (1 mark)
  • Image distance remains unchanged (1 mark)
  • Names the ciliary muscles (½ mark)
  • Role: muscles relax, lens thins, focal length increases (½ 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 paper2024 board paper, set 31/4/1: 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.