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Assertion (A) : All atoms… (Class 12 Physics 2026, Q13)

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PhysicsCBSE Class 12 · Board exam 2026, set 55/1/1 · 1 mark · Assertion-reason

CBSE Class 12 Physics 2026: question 13

Set in the CBSE Class 12 board exam of 2026, paper 55/1/1, section A, question 13, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q13 · 1 mark · Assertion-reasonCompetency-basedMagnetism and Matter

Assertion (A) : All atoms have a net magnetic moment.
Reason (R) : A current loop does not always behave as a magnetic dipole.

  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)Both Assertion (A) and Reason (R) are false.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 55/1/1.

Hints

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

Hint 1

Think of diamagnetic materials.

Hint 2

Does a current loop ever fail to have a magnetic moment IA?

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. The assertion is false: atoms of diamagnetic substances have zero net magnetic moment.

  2. The reason is false: a current loop always behaves as a magnetic dipole with moment . Both are false.

    1 mark

Answer: Option (D)

Where the marks are

  • Identifies both A and R as false (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Magnetism and Matter, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 55/1/1: 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.