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Assertion (A) : Red light… (Class 10 Science 2024, Q19)

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ScienceCBSE Class 10 · Board exam 2024, set 31/3/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2024: question 19

Set in the CBSE Class 10 board exam of 2024, paper 31/3/1, section A, question 19, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q19 · 1 mark · Assertion-reasonCompetency-basedThe Human Eye and the Colourful World

Assertion (A) : Red light signals are used to stop the vehicles on the road.
Reason (R) : Red coloured light is scattered the most so as to be visible from a large distance.

  1. (A)Both (A) and (R) are true and (R) is the correct explanation of (A).
  2. (B)Both (A) and (R) are true and (R) is not correct explanation of (A).
  3. (C)(A) is true, but (R) is false.
  4. (D)(A) is false, but (R) is true.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/3/1.

Hints

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

Hint 1

Scattering depends on wavelength.

Hint 2

Which colour has the longest wavelength, and is it scattered more or less?

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. Assertion is true. Red light is used for stop signals.

  2. Reason is false. Red light has the longest wavelength, so it is scattered the least by fog and smoke. That is why it is seen from far away. Option (C).

    1 mark

Answer: Option (C)

Where the marks are

  • A true, R false because red is scattered least (1 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 31/3/1: 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.