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With the help of the given… (Class 10 Science 2026, Q33)

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

CBSE Class 10 Science 2026: question 33

Set in the CBSE Class 10 board exam of 2026, paper 31/2/1, 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 answerLight – Reflection and Refraction

With the help of the given ray diagram, calculate the refractive index of Medium 2 with respect to Medium 1.

(Given that = 1·732)

Figure in the paper: Horizontal interface separating Medium 1 (above) and Medium 2 (below), with a dashed normal N vertical through point O. Incident ray AO comes from upper left making an angle of 30° with the interface (the horizontal surface). Refracted ray OB goes into Medium 2 making an angle of 30° with the normal. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/2/1.

Hints

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

Hint 1

Angles in Snell's law are measured from the normal, not the surface.

Hint 2

Convert the 30° with the surface into the angle of incidence, then apply sin i / sin r.

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. By Snell's law,

    ½ mark

  2. The incident ray makes 30° with the surface, so . The refracted ray makes 30° with the normal, so .

    1 mark

  3. ½ mark

Answer: Refractive index of Medium 2 w.r.t. Medium 1 = √3 = 1.732

Where the marks are

  • Writes Snell's law sin i / sin r = n (½ mark)
  • Finds i = 60°, r = 30° and substitutes (1 mark)
  • n = √3 = 1.732 (½ 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 31/2/1: 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.