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Refer to the image… (Class 10 Science SQP 2023-24, Q25b)

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ScienceCBSE Class 10 · Sample paper, session 2023-24 · 2 marks · Very short answer

CBSE Class 10 Science sample paper 2023-24: question 25(b)

From the official CBSE sample question paper for 2023-24, section B, question 25(b), for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q25(b) · 2 marks · Very short answerCompetency-basedMagnetic Effects of Electric Current

Refer to the image below and state how the magnetic field pattern indicates regions where the magnetic field is stronger outside the magnet? What happens to the magnetic field when the current in the circuit is reversed?

Figure in the paper: A battery and a variable resistor (rheostat, with arrow) are connected in series to a solenoid. Magnetic field lines are drawn around and through the solenoid, closer together near the ends of the solenoid and spreading out at the sides. Labels: 'solenoid' pointing to the coil and 'magnetic field line' pointing to an outer loop. See it in the official paper.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

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

Hint 1

Look at where the lines in the figure are packed most closely.

Hint 2

The direction of the field around a current-carrying coil depends on the direction of the current.

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. Where the magnetic field lines are closer together (crowded), the magnetic field is stronger.

    ½ mark

  2. Outside the solenoid, the lines are most crowded near its ends (the poles). So the field is strongest near the ends, and it becomes weaker further away, where the lines spread out.

    ½ mark

  3. When the current in the circuit is reversed, the direction of the magnetic field also reverses. The two ends of the solenoid swap their N and S polarities, and the field lines point the opposite way.

    1 mark

Answer: The field is stronger where the lines are crowded, i.e. near the ends (poles) of the solenoid. Reversing the current reverses the direction of the magnetic field (poles interchange).

Where the marks are

  • Crowded field lines indicate a stronger field (0.5 mark)
  • Field is strongest near the ends/poles and weakens away from them (0.5 mark)
  • Reversing the current reverses the field direction (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 paperSample paper 2023-24: 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.