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

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ScienceCBSE Class 10 · Board exam 2024, set 31/2/1 · 1 mark · Assertion-reason

CBSE Class 10 Science 2024: question 20

Set in the CBSE Class 10 board exam of 2024, paper 31/2/1, 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-basedMagnetic Effects of Electric Current

Assertion (A) : The deflection of a compass needle placed near a current carrying wire decreases when the magnitude of an electric current in the wire is increased.
Reason (R) : Strength of the magnetic field at a point due to a current carrying conductor increases on increasing the current in the conductor.

  1. (A)Both (A) and (R) are true and (R) is the correct explanation of (A).
  2. (B)Both (A) and (R) are true, but (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 question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 31/2/1.

Hints

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

Hint 1

How does the field change when the current increases?

Hint 2

Would a stronger field give a smaller or larger deflection?

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. (R) is true: the magnetic field strength increases when the current increases.

    ½ mark

  2. A stronger field deflects the compass needle more, so the deflection increases. (A) is false. Option (D) is correct.

    ½ mark

Answer: Option (D)

Where the marks are

  • Selects option (D) (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 paper2024 board paper, set 31/2/1: 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.