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The resultant magnetic field… (Class 10 Science 2023, Q16)

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ScienceCBSE Class 10 · Board exam 2023, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 16

Set in the CBSE Class 10 board exam of 2023, paper 31/1/1, section A, question 16, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q16 · 1 mark · MCQMagnetic Effects of Electric Current

The resultant magnetic field at point 'P' situated midway between two parallel wires (placed horizontally) each carrying a steady current I is

  1. (A)in the same direction as the current in the wires.
  2. (B)in the vertically upward direction.
  3. (C)zero
  4. (D)in the vertically downward direction.

Figure in the paper: Two horizontal parallel wires AB (top) and CD (bottom), each with current arrow pointing from left to right (A to B, C to D). Point P lies midway between them. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/1/1.

Hints

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

Hint 1

Use the right-hand thumb rule for each wire separately.

Hint 2

P is at the same distance from both wires, and the currents are equal.

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. By the right-hand thumb rule, current from left to right in the top wire AB gives a field at P (below AB) pointing into the page. The same current in the bottom wire CD gives a field at P (above CD) pointing out of the page.

  2. P is equidistant from the two wires and the currents are equal, so the two fields are equal in size and opposite in direction. The resultant field is zero, option (C).

    1 mark

Answer: Zero; option (C)

Where the marks are

  • Recognises equal and opposite fields at P, so the resultant is zero (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 paper2023 board paper, set 31/1/1: 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.