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In the four regions, I, II… (Class 12 Physics 2024, Q8)

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PhysicsCBSE Class 12 · Board exam 2024, set 55/1/1 · 1 mark · MCQ

CBSE Class 12 Physics 2024: question 8

Set in the CBSE Class 12 board exam of 2024, paper 55/1/1, section A, question 8, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q8 · 1 mark · MCQElectromagnetic Waves

In the four regions, I, II, III and IV, the electric fields are described as :
Region I :
Region II :
Region III :
Region IV :
The displacement current will exist in the region :

  1. (A)I
  2. (B)IV
  3. (C)II
  4. (D)III

Source: official question paper from cbse.gov.in (PDF). See it in the full 2024 board paper, set 55/1/1.

Hints

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

Hint 1

What does displacement current depend on?

Hint 2

Check which expression contains t.

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. Displacement current is , so it exists only where E changes with time.

  2. Only in region I, , does the field depend on t. In the other three regions the field is independent of time. Option (A).

    1 mark

Answer: Region I, option (A)

Where the marks are

  • Identifies that displacement current needs a time-varying E, which occurs only in region I (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 paper2024 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.