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Assertion (A): Magnetic field… (Class 10 Science 2025, Q19)

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ScienceCBSE Class 10 · Board exam 2025, set 31/3/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2025: question 19

Set in the CBSE Class 10 board exam of 2025, 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-basedMagnetic Effects of Electric Current

Assertion (A): Magnetic field lines around a bar magnet never intersect each other.

Reason (R): Magnetic field produced by a bar magnet is a quantity that has both magnitude and direction.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of 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 2025 board paper, set 31/3/1.

Hints

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

Hint 1

What would two directions at one point mean?

Hint 2

Does R state that fact?

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. Both statements are true: field lines never cross, and the magnetic field has both magnitude and direction.

    ½ mark

  2. Field lines do not cross because the field can have only one direction at any point. R states only that the field is a vector, so the scheme treats it as not the correct explanation.

    ½ mark

Answer: Option (B)

Where the marks are

  • Both true, R not the correct explanation (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Magnetic Effects of Electric Current, one at a time, marked against the answer key and marking points.Back to the full paper2025 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.