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A. Define mutual… (Class 12 Physics SQP 2023-24, Q28a)

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PhysicsCBSE Class 12 · Sample paper, session 2023-24 · 3 marks · Short answer

CBSE Class 12 Physics sample paper 2023-24: question 28(a)

From the official CBSE sample question paper for 2023-24, section C, question 28(a), for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q28(a) · 3 marks · Short answerElectromagnetic Induction

a. Define mutual inductance and write its SI unit.
b. Two circular loops, one of small radius r and other of larger radius R, such that R >> r, are placed coaxially with centres coinciding. Obtain the mutual inductance of the arrangement.

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

Pass current through the larger loop, because its field at the centre is easy to find.

Hint 2

The small loop sees an almost uniform field; flux = B × area, and M = flux/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. Mutual inductance of two coils is the magnetic flux linked with one coil per unit current in the other (). Equivalently, it equals the emf induced in one coil per unit rate of change of current in the other.

    ½ mark

  2. SI unit: henry (H).

    ½ mark

  3. Let current flow in the large loop of radius R. Field at its centre: .

    ½ mark

  4. Since , this field is nearly uniform over the small loop. Flux through small loop: .

    ½ mark

  5. Also .

    ½ mark

  6. ½ mark

Answer: Unit: henry;

Where the marks are

  • Correct definition of mutual inductance (½ mark)
  • SI unit henry (½ mark)
  • Field at centre of large loop (½ mark)
  • Flux through small loop (½ mark)
  • Uses (½ mark)
  • Obtains (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Electromagnetic Induction, 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.