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Assertion (A): Ozone layer… (Class 10 Science 2024, Q20)

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ScienceCBSE Class 10 · Board exam 2024, set 31/5/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2024: question 20

Set in the CBSE Class 10 board exam of 2024, paper 31/5/1, section A, question 20, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q20 · 1 mark · Assertion-reasonCompetency-basedOur Environment

Assertion (A): Ozone layer protects the surface of the Earth from harmful UV radiations.

Reason (R): Chlorofluorocarbons (CFCs) are responsible for depletion of ozone layer.

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

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/5/1.

Hints

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

Hint 1

Test each statement separately.

Hint 2

Does the cause of depletion explain the protective role?

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. Ozone does absorb harmful UV radiation, and CFCs do deplete the ozone layer, so both statements are true.

  2. Ozone depletion by CFCs does not explain why ozone protects the Earth. Option (B).

    1 mark

Answer: Option (B)

Where the marks are

  • Chooses (B) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Our Environment, one at a time, marked against the answer key and marking points.Back to the full paper2024 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.