Semiconductors — Class 11 MCQs with Answers
Class 11 CBSE Physics · Chapter 308
40 practice questions · 20 Easy · 20 Medium · Updated
Practise the most important Class 11 CBSE Physics questions from Chapter 308, "Semiconductors". You get 4 timed quizzes made from 40 NCERT-based MCQs, with answers and explanations. The questions are split into 20 Easy and 20 Medium. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG apart.
To score well in "Semiconductors", focus on numericals, derivations and applying concepts. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Semiconductors, then move to Medium to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Physics mastery score. 6 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Semiconductors (Class 11 Physics)
From energy bands to working devices: how band gaps separate conductors, insulators and semiconductors, intrinsic conduction by electrons and holes, doping to make n-type and p-type material, the pn junction with its depletion region and barrier potential, forward and reverse bias, rectification, and the special-purpose diodes.
- Energy bands in solids
- Atomic energy levels broaden into bands when atoms come together, with a forbidden energy gap separating the filled valence band from the empty conduction band.
- Conductors, insulators, semiconductors
- In a conductor the bands overlap; an insulator has a gap above about 3 eV; a semiconductor's gap is small enough for thermal energy to bridge it.
- Band gap
- Silicon's gap is about 1.1 eV and germanium's about 0.7 eV at room temperature. The smaller gap makes germanium the more thermally sensitive of the two.
- Intrinsic semiconductor
- Pure semiconductor in which electrons and holes are created only in pairs by thermal excitation, so their concentrations are exactly equal.
Semiconductors — important questions & MCQs with answers (Class 11 Physics)
6 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 34 are timed and scored when you sign in.
- Q1Easy
Pure silicon is an example of which type of material?
A.ConductorB.Intrinsic semiconductor✓ CorrectC.InsulatorD.SuperconductorAnswer: B. Intrinsic semiconductor
Explanation: Pure Si has a moderate band gap (~1.1 eV) and is an intrinsic semiconductor.
- Q2Easy
The barrier potential of a silicon pn-junction diode is approximately:
A.0.7 V✓ CorrectB.0.3 VC.1.5 VD.5 VAnswer: A. 0.7 V
Explanation: Si diode knee voltage is about 0.7 V; Ge is about 0.3 V.
- Q3Easy
Adding a pentavalent impurity to silicon gives which type of semiconductor?
A.InsulatorB.p-typeC.n-type✓ CorrectD.ConductorAnswer: C. n-type
Explanation: Pentavalent donors provide an extra electron, producing an n-type semiconductor.
- Q4Medium
In an extrinsic semiconductor at thermal equilibrium, the product of electron and hole concentrations equals:
A.Nᴀ × NᴅB.nᵢC.nᵢ²✓ CorrectD.ZeroAnswer: C. nᵢ²
Explanation: Mass-action law: n·p = nᵢ² at equilibrium.
- Q5Medium
A forward-biased pn-junction diode behaves as:
A.A heating element onlyB.An open circuitC.A high resistance pathD.A low resistance path✓ CorrectAnswer: D. A low resistance path
Explanation: Forward bias narrows depletion region, allowing easy current flow.
- Q6Medium
In a pure (intrinsic) semiconductor, the Fermi level lies approximately:
A.In the conduction bandB.Near the middle of the band gap✓ CorrectC.In the valence bandD.Above the conduction bandAnswer: B. Near the middle of the band gap
Explanation: Equal carrier concentrations place Eꜰ near mid-gap in intrinsic material.
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Start this chapter free →Semiconductors — FAQs
What are the key concepts in Class 11 Physics Semiconductors?+
From energy bands to working devices: how band gaps separate conductors, insulators and semiconductors, intrinsic conduction by electrons and holes, doping to make n-type and p-type material, the pn junction with its depletion region and barrier potential, forward and reverse bias, rectification, and the special-purpose diodes. Key ideas include Energy bands in solids, Conductors, insulators, semiconductors, Band gap, Intrinsic semiconductor.
What does Class 11 Physics Chapter 308 (Semiconductors) cover on XamBaaz?+
It has 40 NCERT-based MCQs on "Semiconductors": 20 Easy and 20 Medium. Together they make 4 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, JEE Main, MHT-CET, JEE Advanced and NEET UG.
Are these "Semiconductors" questions free to practise?+
Yes. Sign in with Google to practise "Semiconductors" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Semiconductors" for the exam?+
Start with the Easy quiz to check your basics, then try Medium to practise applying them. There are 4 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Semiconductors" MCQs available with answers?+
Yes. 6 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Semiconductors" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as JEE Main, JEE Advanced and NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Semiconductors (Class 11 Physics)?+
The questions that matter most test Energy bands in solids, Conductors, insulators, semiconductors, Band gap, Intrinsic semiconductor. This page shows 6 solved important MCQs with answers and explanations; all 40 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Semiconductors?+
Yes — Class 11 Physics Semiconductors has timed online quizzes at Easy and Medium levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.