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State two laws of refraction… (Class 10 Science 2024, Q24a)

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 2 marks · Very short answer

CBSE Class 10 Science 2024: question 24(a)

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, section B, question 24(a), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q24(a) · 2 marks · Very short answerLight – Reflection and Refraction

State two laws of refraction of light.

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

Think about where the three lines (incident ray, refracted ray, normal) lie.

Hint 2

The second law links the angle of incidence and the angle of refraction through their sines.

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. First law of refraction: The incident ray, the refracted ray and the normal drawn to the interface of the two transparent media at the point of incidence all lie in the same plane.

    1 mark

  2. Second law of refraction (Snell's law): For light of a given colour and a given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant. That is, . This constant is the refractive index of the second medium with respect to the first.

    1 mark

Answer: (1) Incident ray, refracted ray and normal at the point of incidence lie in one plane. (2) is constant for a given colour and a given pair of media (Snell's law).

Where the marks are

  • States that the incident ray, the refracted ray and the normal lie in the same plane (1 mark)
  • States Snell's law in words, mentioning a given colour of light and a given pair of media (1 mark); only writing = constant without the statement earns 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 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.