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Consider an induced magnetic… (Class 12 Physics 2023, Q20)

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PhysicsCBSE Class 12 · Board exam 2023, set 55/1/1 · 2 marks · Very short answer

CBSE Class 12 Physics 2023: question 20

Set in the CBSE Class 12 board exam of 2023, paper 55/1/1, section B, question 20, for 2 marks. Try it first; the hints and our step-by-step solution are below.

Q20 · 2 marks · Very short answerElectromagnetic Waves

Consider an induced magnetic field due to changing electric field and an induced electric field due to changing magnetic field. Which one is more easily observed ? Justify your answer.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 55/1/1.

Hints

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

Hint 1

Think of which effect you have seen in the lab with a coil, magnet and galvanometer.

Hint 2

Compare Faraday's law with the displacement current term — how large is ?

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. The induced electric field due to a changing magnetic field (electromagnetic induction) is more easily observed.

    1 mark

  2. Justification: an induced emf/current is readily produced and detected in everyday ways — moving a bar magnet towards a coil, rotating or moving a coil in a magnetic field, changing the area/shape of a coil in a field (as in generators and transformers). In contrast, the magnetic field due to a changing electric field (displacement current ) is extremely small because is very small, so it needs very rapidly varying fields to be noticed.

    1 mark

Answer: Induced electric field due to changing magnetic field is more easily observed.

Where the marks are

  • Correct identification: induced electric field due to changing magnetic field (1 mark)
  • Justification: easily produced by moving magnet/coil, changing area etc.; displacement current effect is tiny (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Electromagnetic Waves, one at a time, marked against the answer key and marking points.Back to the full paper2023 board paper, set 55/1/1: 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.