Topic 2 of 5 โข Chapter: Electronics โข Physics
Energy Bands and Semiconductors โ Complete Notes, Revision, Important Questions & Downloads
Energy Bands and Semiconductors in Electronics is built around Energy Band Theory, Holes in Semiconductors, Intrinsic Semiconductors, Extrinsic Semiconductors, N-Type Semiconductor, P-Type Semiconductor, Semiconductor Conductivity, P-N Junction Diode, Biasing in P-N Diodes, Reverse Breakdown Mechanisms, Special Purpose Diodes. NEET tests Energy Bands and Semiconductors by asking you to identify which of these exact subtopics controls the setup, then apply the correct relation, sign convention, or limiting condition. A standard trigger is ฮEg = (C.B.)min - (V.B.)max, so the safe route is to map the wording back to the exact subtopic before any substitution. This page stays inside the Class 12 NEET scope: it keeps the textbook definitions, adds the exam-useful trap checks, and avoids university-level extensions that are outside the assigned OCR pages.
11 SubtopicsTheoryMedium Difficulty
Expected QuestionsQ
1-2
Energy Bands and Semiconductors usually appears as a direct NEET tool: sometimes direct, often embedded inside a larger electronics calculation or concept check.
Time Requiredโฑ
3-3.5 hrs
One pass to lock the formula or definition of each subtopic, one pass to solve NEET-style stems that force you to choose between nearby relations from Energy Bands and Semiconductors.
Difficultyโก
Medium
Energy Bands and Semiconductors is medium because the arithmetic is rarely the real issue; the real filter is whether you recognize the exact condition behind the active subtopic quickly enough.
NRI USA Curriculum GapUS
Medium
AP Physics 2 and AP Physics C usually cover the broad physics idea, but NEET expects faster textbook-speed recognition of Energy Bands and Semiconductors, especially the short trigger conditions attached to Energy Band Theory.
11Subtopics
11Practice Questions
4Free Downloads
3-3.5 hrsPrep Time
NEET Weightage โ Energy Bands and Semiconductors
Electronics (Chapter 27)| NEET Year | Questions from this Topic | Bar | Marks |
|---|---|---|---|
| 2024 | 1 | 4 | |
| 2023 | 0 | 0 | |
| 2022 | 1 | 4 | |
| 2021 | 0 | 0 | |
| 2020 | 1 | 4 | |
| 2019 | 0 | 0 | |
| 6-Year Pattern (2019โ2024) | 1-2 | ย | 4-8 |
Energy Bands and Semiconductors is usually unlocked by spotting the right subtopic first: Energy Band Theory is rarely interchangeable with the rest of the chapter even when the symbols look familiar.
The chapter emphasis is operational rather than decorative: NEET asks you to use Energy Bands and Semiconductors inside a live setup, not just repeat the definition of Holes in Semiconductors.
The most reliable mark-saving habit in Energy Bands and Semiconductors is to check sign, medium, geometry, or device condition before simplifying the formula.
The chapter emphasis is operational rather than decorative: NEET asks you to use Energy Bands and Semiconductors inside a live setup, not just repeat the definition of Holes in Semiconductors.
The most reliable mark-saving habit in Energy Bands and Semiconductors is to check sign, medium, geometry, or device condition before simplifying the formula.
1-2
Avg Questions / Year
4-8
Total Marks (6 yrs)
Direct
Pattern
Medium
Difficulty
Exam Strategy for Energy Bands and Semiconductors
1
Lock one usable relation for each Energy Bands and Semiconductors subtopic Write the main relation or textbook sentence for Energy Band Theory, Holes in Semiconductors, Intrinsic Semiconductors, Extrinsic Semiconductors. Attach one condition of validity to each so you know when the relation can actually be used in NEET.
2
Classify the stem before calculating Decide whether the problem is asking for magnitude, direction, image position, current, device action, carrier behavior, or communication mode. That classification tells you which part of Energy Bands and Semiconductors is active.
3
Run one trap check before marking the answer For Energy Bands and Semiconductors, the final mistake is usually not algebra; it is a missed sign convention, wrong medium, wrong branch of a device characteristic, or confusion between two nearby subtopics. Check that before you stop.
4
Revise Energy Bands and Semiconductors with mixed stems, not isolated notes After revising the page once, solve short chapter-level questions that force you to distinguish Energy Band Theory from the neighboring ideas. That is much closer to the way NEET actually uses this topic.
Download Study Notes โ Energy Bands and Semiconductors
PDF ยท Cheat Sheet ยท MCQ Set ยท PYQEnergy Bands and Semiconductors โ Full Notes
Complete topic notes covering all 11 subtopics in Energy Bands and Semiconductors, with the governing relation, the validity condition, and one worked example per subtopic.
Download PDFEnergy Bands and Semiconductors โ Formula Sheet
One-page formula sheet for Energy Bands and Semiconductors: compact relations, sign conventions, and short reminders of where each formula is valid.
Download PDFEnergy Bands and Semiconductors โ MCQ Practice
11 application-driven MCQ practice questions built from the same setups, devices, or optical geometries that NEET uses in Energy Bands and Semiconductors.
Download PDFEnergy Bands and Semiconductors โ PYQ Practice
NEET-style PYQ practice set for Energy Bands and Semiconductors that highlights the shortest reliable route from the active subtopic to the correct answer.
Download PDFSubtopics in Energy Bands and Semiconductors
2-Column TableRapid Revision โ Energy Bands and Semiconductors
Concept โ Trap โ Example1) Energy Band Theory
Definition + ApplicationEnergy band formed by series of energy levels containing valence electrons. Always filled with electrons. Highest energy band. Electrons cannot gain energy from external electric field. No current flow.
- Use Energy Band Theory only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Energy Band Theory, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Energy Band Theory: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
2) Holes in Semiconductors
Definition + ApplicationA vacancy created when an electron is removed from a covalent bond. Can travel through material and serve as charge carrier. Considered as positive charge with magnitude equal to electron charge. Virtual charge with no actual physical charge.
- Use Holes in Semiconductors only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Holes in Semiconductors, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Holes in Semiconductors: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
3) Intrinsic Semiconductors
Formula + ApplicationPure semiconductor with thermally generated current carriers. Four valence electrons with atoms held by covalent bonds. Free electrons equal holes (n_e = n_h = n_i). Low conductivity due to fewer charge carriers. No practical use.
- Use Intrinsic Semiconductors only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Intrinsic Semiconductors, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Intrinsic Semiconductors: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: a 100 W, 200 V bulb connected to 100 V draws 25 W because power scales as V^2 when the resistance of the filament is unchanged.
4) Extrinsic Semiconductors
Definition + ApplicationImpure semiconductor where small amounts of specific impurities with different valency are added to parent material. Process called doping. Drastically changes number of mobile electrons/holes.
- Use Extrinsic Semiconductors only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Extrinsic Semiconductors, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Extrinsic Semiconductors: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
5) N-Type Semiconductor
Definition + ApplicationObtained by adding small amount of pentavalent impurity to pure semiconductor (Ge). Majority carriers: electrons. Minority carriers: holes. n_e >> n_h. Donor impurity provides one electron. Neutral semiconductor (not negatively charged).
- Use N-Type Semiconductor only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in N-Type Semiconductor, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in N-Type Semiconductor: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
6) P-Type Semiconductor
Definition + ApplicationObtained by adding small amount of trivalent impurity to pure semiconductor (Ge). Majority carriers: holes. Minority carriers: electrons. n_h >> n_e. Acceptor impurity accepts electrons. Neutral semiconductor (not positively charged).
- Use P-Type Semiconductor only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in P-Type Semiconductor, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in P-Type Semiconductor: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
7) Semiconductor Conductivity
Formula + Applicationฯ = e[n_e ร ฮผ_e + n_h ร ฮผ_h], where n_e = electron density, n_h = hole density, ฮผ_e = electron mobility, ฮผ_h = hole mobility
- Use Semiconductor Conductivity only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Semiconductor Conductivity, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Semiconductor Conductivity: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
8) P-N Junction Diode
Definition + ApplicationArrangement formed when P-type semiconductor is suitably joined to N-type semiconductor.
- Use P-N Junction Diode only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in P-N Junction Diode, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in P-N Junction Diode: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
9) Biasing in P-N Diodes
Formula + ApplicationPositive terminal connected to P-crystal, negative to N-crystal. Decreases depletion layer width. Forward resistance = 10ฮฉ - 25ฮฉ. Opposes potential barrier. For V > V_B, forward current flows: i = i_s(e^(eV/kT) - 1).
- Use Biasing in P-N Diodes only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Biasing in P-N Diodes, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Biasing in P-N Diodes: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
10) Reverse Breakdown Mechanisms
Definition + ApplicationWhen reverse bias increases, electric field breaks covalent bonds directly, creating electron-hole pairs and large current. Occurs at specific voltage.
- Use Reverse Breakdown Mechanisms only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Reverse Breakdown Mechanisms, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Reverse Breakdown Mechanisms: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
11) Special Purpose Diodes
Definition + ApplicationHighly doped P-N junction not damaged by high reverse current. Operates continuously in reverse breakdown region without damage. Forward bias: acts as ordinary diode. Used as voltage regulator.
- Use Special Purpose Diodes only when the stem is explicitly controlled by that exact physical object, device block, optical geometry, or transmission mode.
- Before calculating in Special Purpose Diodes, check the validity condition mentioned in the page: sign convention, medium, current direction, carrier type, or image-formation rule.
- Trap in Special Purpose Diodes: device questions reward correct terminal or carrier identification; the common error is to mix the role of majority carriers, current direction, or gate truth condition.
Example (NEET-style)Example: silicon doped with phosphorus becomes n-type because each donor atom contributes one extra electron, so electrons become the majority carriers.
US Curriculum Gaps โ Energy Bands and Semiconductors
Students coming from AP Physics 2 or AP Physics C often know the big picture but need extra speed on the NCERT-style trigger conditions inside Energy Bands and Semiconductors.AP Physics 2 does not train the same textbook trigger recognition used in Energy Bands and Semiconductors
US courses usually explain the broad idea well, but NEET expects you to identify whether the active piece is Energy Band Theory or another nearby subtopic in seconds, not after a long free-response setup.
- AP questions often allow more working space, while NEET compresses Energy Bands and Semiconductors into fast elimination built around one decisive condition.
- Make one trigger line for Energy Band Theory so you can spot it instantly in a mixed chapter stem.
- Practice short MCQs that separate Energy Band Theory from the neighboring ideas instead of revising only long descriptive notes.
AP Physics C covers principles, but NEET expects faster use of Holes in Semiconductors
Even strong AP students lose marks when they know the principle but miss the specific sign, device branch, or geometry cue that tells them Holes in Semiconductors is the controlling idea in the NEET question.
- Keep the formula and the condition of validity together for each Energy Bands and Semiconductors subtopic.
- Translate every long stem into the exact subtopic name before writing equations.
- Use a final trap check for sign, medium, current direction, or image orientation before accepting the answer.
NEET-style Practice Questions โ Energy Bands and Semiconductors
11 NEET-style application questions1Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Energy Band Theory. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
2Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Holes in Semiconductors. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
3A 100 W, 200 V bulb is connected to a 100 V source. Assuming the filament resistance stays unchanged, the power consumed is nearest toNEET-style application
25 W
50 W
100 W
200 W
Resistance of the bulb at rated values is R = V^2/P = 200^2/100 = 400 ohm. At 100 V, the new power is P = V^2/R = 100^2/400 = 25 W. The 50 W and 100 W options ignore the square dependence on voltage, while 200 W would require the supply voltage to rise, not fall. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Intrinsic Semiconductors. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
4Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Extrinsic Semiconductors. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
5Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to N-Type Semiconductor. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
6Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to P-Type Semiconductor. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
7Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Semiconductor Conductivity. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
8Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to P-N Junction Diode. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
9Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Biasing in P-N Diodes. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
10Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Reverse Breakdown Mechanisms. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
11Silicon doped with phosphorus behaves asNEET-style application
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal. The first job is to identify the active subtopic, because NEET almost never rewards blind formula substitution in Energy Bands and Semiconductors. Once the setup is classified, the correct option follows from the textbook relation attached to Special Purpose Diodes. The remaining options are attractive because they echo a nearby chapter rule, reverse a sign convention, or ignore the stated device or medium condition, which is exactly how this topic produces traps in single-correct MCQs.
Practice Problems โ Energy Bands and Semiconductors
Click "Reveal Answer" after attempting1Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
2Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
3A 100 W, 200 V bulb is connected to a 100 V source. Assuming the filament resistance stays unchanged, the power consumed is nearest to
25 W
50 W
100 W
200 W
๐ Reveal Answer
Option 1 is correct. Resistance of the bulb at rated values is R = V^2/P = 200^2/100 = 400 ohm. At 100 V, the new power is P = V^2/R = 100^2/400 = 25 W. The 50 W and 100 W options ignore the square dependence on voltage, while 200 W would require the supply voltage to rise, not fall.
4Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
5Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
6Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
7Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
8Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
9Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
10Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
11Silicon doped with phosphorus behaves as
an n-type semiconductor with electrons as majority carriers
a p-type semiconductor with holes as majority carriers
an insulator because donor atoms block conduction
a metal because the band gap becomes zero
๐ Reveal Answer
Option 1 is correct. Phosphorus is pentavalent, so each donor atom contributes one extra electron that is only weakly bound. That makes the crystal n-type with electrons as majority carriers. It does not create holes as the majority carriers, does not turn the solid into an insulator, and does not collapse the semiconductor band gap to zero like a metal.
Physics โ Energy Bands and Semiconductors Revision Checklist
Check off chapters as you revise
Use this section for quick chapter tracking before mocks, part tests, and final NEET revision.
FAQs โ Energy Bands and Semiconductors
Notes ยท Downloads ยท Revision ยท Important QuestionsHow do I know a question really belongs to Energy Bands and Semiconductors and not to a neighboring chapter idea?
Read the physical quantity and the condition before reading the numbers. If the stem is truly about Energy Bands and Semiconductors, one of the listed subtopics on this page will name the controlling object, device state, image rule, or communication mode directly. That classification step is more reliable than chasing a familiar formula first.
Which Energy Bands and Semiconductors subtopic should I identify first in a mixed NEET question?
Start with the subtopic that names the decisive condition in the wording. If the question explicitly points toward Energy Band Theory, write that relation first and only then ask whether another chapter relation must be combined with it.
What is the most common sign or condition mistake in Energy Bands and Semiconductors?
The biggest mark-loss pattern in Energy Bands and Semiconductors is skipping the condition of validity. Students often remember the formula but forget the sign convention, medium, current direction, device branch, or geometry cue that makes the formula legal in that setup.
How much formula memorisation is enough for Energy Bands and Semiconductors?
Memorise one dependable rule or relation per subtopic, not a pile of look-alike formulas. Pair each relation with one trigger sentence so you know when it is safe to use it in NEET.
Why does NEET often hide Energy Bands and Semiconductors inside longer chapter questions?
Because Energy Bands and Semiconductors often acts as the hinge that converts a descriptive stem into a solvable one. NEET therefore embeds it inside larger questions to test whether you can isolate the operative idea quickly instead of treating the whole chapter as one undifferentiated block.
How should an NRI student bridge the gap for Energy Bands and Semiconductors?
Use AP Physics 2 or AP Physics C only for broad comfort, then train yourself on textbook-speed recognition of Energy Bands and Semiconductors. Short MCQs that contrast nearby subtopics are more useful here than long derivations alone.
What should I revise on the last day for Energy Bands and Semiconductors?
On the last day, revise the subtopic list itself, the first formula or definition tied to each subtopic, and one trap from each. For Energy Bands and Semiconductors, that compact pass is usually more effective than rereading all chapter prose.
How do I stop mixing Energy Band Theory with Holes in Semiconductors?
Write the deciding difference in one line. For example, note what makes Energy Band Theory active and what makes Holes in Semiconductors active, then solve two short stems back-to-back until the trigger words stop competing with each other.
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