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A p-n junction diode is… (Class 12 Physics 2025, Q11)

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PhysicsCBSE Class 12 · Board exam 2025, set 55/7/1 · 1 mark · MCQ

CBSE Class 12 Physics 2025: question 11

Set in the CBSE Class 12 board exam of 2025, paper 55/7/1, section A, question 11, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q11 · 1 mark · MCQSemiconductor Electronics: Materials, Devices and Simple Circuits

A p-n junction diode is forward biased. As a result,

  1. (A)both the potential barrier height and the width of depletion layer decrease.
  2. (B)both the potential barrier height and the width of depletion layer increase.
  3. (C)the potential barrier height decreases and the width of depletion layer increases.
  4. (D)the potential barrier height increases and the width of depletion layer decreases.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 55/7/1.

Hints

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

Hint 1

Does forward bias aid or oppose the built-in field?

Hint 2

What happens to the uncovered ions near the junction?

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. In forward bias, the applied voltage opposes the barrier potential, so the barrier height falls to .

    ½ mark

  2. Majority carriers are pushed towards the junction, so the depletion layer narrows.

    ½ mark

Answer: Option (A)

Where the marks are

  • States that both barrier height and depletion width decrease (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Semiconductor Electronics: Materials, Devices and Simple Circuits, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 55/7/1: 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.