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Assertion (A): A… (Class 10 Science SQP 2024-25, Q19)

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ScienceCBSE Class 10 · Sample paper, session 2024-25 · 1 mark · Assertion-reason

CBSE Class 10 Science sample paper 2024-25: question 19

From the official CBSE sample question paper for 2024-25, 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-basedLight – Reflection and Refraction

Assertion (A): A convex mirror always forms an image behind it and the image formed is virtual.
Reason (R): According to the sign convention, the focal length of a convex mirror is positive.

  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 the correct explanation of A.
  3. (C)A is true but R is false.
  4. (D)A is false but R is true

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2024-25.

Hints

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

Hint 1

Draw the reflected rays for a convex mirror. Do they meet in front of it?

Hint 2

Does a sign convention cause a physical effect?

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. For every position of the object, a convex mirror forms a virtual, erect, diminished image behind the mirror. A is true. By the sign convention, the focus lies behind the mirror, so its focal length is positive. R is true.

    ½ mark

  2. The positive sign is only a convention and does not explain why the image is always virtual. That happens because the reflected rays diverge. The answer is option (B).

    ½ mark

Answer: Both true, R not the explanation; option (B)

Where the marks are

  • Recognises both statements as true but R as not the explanation (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 paperSample paper 2024-25: 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.