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(a) Relate the speed of light… (Class 10 Science 2026, Q33)

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ScienceCBSE Class 10 · Board exam 2026, set 31/5/1 · 2 marks · Very short answer

CBSE Class 10 Science 2026: question 33

Set in the CBSE Class 10 board exam of 2026, paper 31/5/1, section C, question 33, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q33 · 2 marks · Very short answerCompetency-basedLight – Reflection and Refraction

(a) Relate the speed of light in the given medium with its optical density.

(b) Using the information given in the table below, arrange the medium A, B and C in the ascending order of their optical density.

MediumSpeed of light (m/s)
A
B
C
  1. (a)

    Relate the speed of light in the given medium with its optical density.

    0 marks
  2. (b)

    Arrange the medium A, B and C in the ascending order of their optical density, using the table.

    0 marks

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/5/1.

Hints

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

Hint 1

Light slows down when it enters glass from air; glass is denser optically.

Hint 2

Arrange the speeds from highest to lowest, then reverse the idea for optical density.

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) Speed of light is more in an optically rarer medium and less in an optically denser medium, i.e. the greater the optical density, the smaller the speed of light.

    1 mark

  2. (b) Speeds: A () > C () > B ( m/s). Lower speed means higher optical density, so ascending order of optical density: A < C < B.

    1 mark

Answer: (a) Higher optical density → lower speed of light; (b) A < C < B

Where the marks are

  • Correct relation between speed and optical density (1 mark)
  • Order A < C < B (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Light – Reflection and Refraction, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/5/1: 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.