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For the current carrying… (Class 10 Science 2023, Q32B)

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ScienceCBSE Class 10 · Board exam 2023, set 31/4/1 · 3 marks · Short answer

CBSE Class 10 Science 2023: question 32(B)

Set in the CBSE Class 10 board exam of 2023, paper 31/4/1, section C, question 32(B), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q32(B) · 3 marks · Short answerMagnetic Effects of Electric Current

For the current carrying solenoid as shown, draw magnetic field lines and give reason to explain that out of the three points A, B and C, at which point the field strength is maximum and at which point it is minimum ?

Figure in the paper: A horizontal current carrying solenoid (cylindrical coil) with current arrows on the lower side. Three points marked: A inside the solenoid near its centre, B just above the solenoid, and C to the left of the solenoid outside its end. See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/4/1.

Hints

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

Hint 1

The field of a solenoid looks like that of a bar magnet.

Hint 2

Field strength is shown by how close together the field lines are.

Hint 3

Compare a point inside, a point beside the middle outside, and a point near an end.

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. Diagram (described): inside the solenoid, draw straight, parallel, closely spaced field lines along the axis. Outside, the lines emerge from one end (N) and curve around to re-enter the other end (S), like a bar magnet. Mark the direction of current in the turns and the direction of the field lines with arrows, using the right-hand thumb rule.

    1 mark

  2. Field is maximum at A (inside the solenoid).

    ½ mark

  3. Reason: inside, the field lines are crowded together and uniform, because the fields of all turns add up.

    ½ mark

  4. Field is minimum at B (just outside, beside the middle of the solenoid).

    ½ mark

  5. Reason: there the field lines are far apart. Point C near the end is closer to a pole, where the lines are more concentrated than at B.

    ½ mark

Answer: Maximum at A (crowded, uniform lines inside); minimum at B (lines far apart outside)

Where the marks are

  • Correct field line pattern with current and field directions; ½ deducted if directions missing (1 mark)
  • Maximum at A (½ mark)
  • Reason: lines crowded / fields of turns add up (½ mark)
  • Minimum at B (½ mark)
  • Reason: lines far apart (½ 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 31/4/1: 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.