Skip to content

Define the term power of… (Class 10 Science 2024, Q31a)

questionbuddy.in/q/cbse-10-science-2024-31-2-1-q31a-define-term-power-accommodation-human

ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 3 marks · Short answer

CBSE Class 10 Science 2024: question 31(a)

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section C, question 31(a), for 3 marks. Try it first; the hints and our step-by-step solution are below.

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

Define the term power of accommodation of human eye. Write the name of the part of eye which plays a major role in the process of accommodation and explain what happens when human eye focuses (i) nearby objects and (ii) distant objects.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

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

Hint 1

Which property of the lens must change to see near and far objects clearly?

Hint 2

Muscles attached to the lens change its thickness; link thickness to focal length.

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: 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 ciliary muscles play the major role by changing the curvature of the eye lens.

    1 mark

  3. (i) Nearby objects: the ciliary muscles contract, the lens becomes thicker (more curved) and its focal length decreases.

    ½ mark

  4. (ii) Distant objects: the ciliary muscles relax, the lens becomes thinner and its focal length increases.

    ½ mark

Answer: Ability of the eye lens to adjust its focal length; ciliary muscles; near: muscles contract, lens thick, focal length decreases; distant: muscles relax, lens thin, focal length increases.

Where the marks are

  • Definition of power of accommodation (1 mark)
  • Ciliary muscles (1 mark)
  • Near object: contract, thick lens, shorter focal length (½ mark)
  • Distant object: relax, thin lens, longer focal length (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 31/2/1: 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.