Bihar Board Class 12 Physics Chapter-Wise Weightage 2027: Most Important Chapters from 9 Past Papers
Counted from every Bihar Board Intermediate Physics paper from 2017 to 2026 (9 papers), question by question.
The short answer
Across the six papers set in the current pattern (2021–2026), the chapters that carried the most printed marks were:
- Ray Optics and Optical Instruments: 15.1% of the printed marks
- Current Electricity: 9.3% of the printed marks
- Electric Charges and Fields: 9.3% of the printed marks
- Alternating Current: 9.0% of the printed marks
- Semiconductor Electronics: 9.0% of the printed marks
Taken as a unit, Optics (ray optics and wave optics together) is 21.4% of what was asked, the largest unit. BSEB’s own syllabus gives Optics 14 of the 70 marks, also the largest.
Key insight. BSEB prints twice as many questions as you answer, so a chapter’s share of the printed paper tells you how many chances it gives you, not how many marks you must score from it. A strong chapter with many questions is a safe place to collect your 35 objective marks.
How the paper is set
The theory paper is out of 70 marks and lasts 3 hours 15 minutes, which includes 15 minutes to read the questions. Since 2021 it has had three parts:
| Part | Printed | You answer | Marks |
|---|---|---|---|
| Objective (OMR) | 70 questions | any 35 | 35 × 1 = 35 |
| Short answer | 20 questions | any 10 | 10 × 2 = 20 |
| Long answer | 6 questions | any 3 | 3 × 5 = 15 |
So 140 marks’ worth of questions are printed for a 70-mark paper. Every percentage on this page is a share of those 140 printed marks.
Chapter-wise weightage, 2021–2026
Average printed marks a year, split into the objective and the written parts. Each row links to that chapter’s Bihar Board questions on our tests site, and to our NCERT solutions for the chapter.
| Chapter | Unit (इकाई) | Share | Objective marks a year | Written marks a year | ||
|---|---|---|---|---|---|---|
| Ray Optics and Optical Instruments | VI · प्रकाशिकी | 15.1% | 8.7 | 12.5 | Practise | NCERT |
| Current Electricity | II · धारा-विद्युत् | 9.3% | 7.3 | 5.7 | Practise | NCERT |
| Electric Charges and Fields | I · विद्युत् स्थैतिकी | 9.3% | 7.5 | 5.5 | Practise | NCERT |
| Alternating Current | IV · विद्युत् चुम्बकीय प्रेरण एवं प्रत्यावर्ती धारा | 9.0% | 5.7 | 7.0 | Practise | NCERT |
| Semiconductor Electronics | IX · इलेक्ट्रॉनिक युक्तियाँ | 9.0% | 5.0 | 7.7 | Practise | NCERT |
| Electrostatic Potential and Capacitance | I · विद्युत् स्थैतिकी | 7.9% | 6.8 | 4.2 | Practise | NCERT |
| Magnetism and Matter | III · विद्युत् धारा के चुम्बकीय प्रभाव एवं चुम्बकत्व | 7.7% | 4.7 | 6.2 | Practise | NCERT |
| Wave Optics | VI · प्रकाशिकी | 6.3% | 3.7 | 5.2 | Practise | NCERT |
| Moving Charges and Magnetism | III · विद्युत् धारा के चुम्बकीय प्रभाव एवं चुम्बकत्व | 5.8% | 4.2 | 4.0 | Practise | NCERT |
| Nuclei | VIII · परमाणु एवं नाभिक | 5.1% | 3.7 | 3.5 | Practise | NCERT |
| Dual Nature of Radiation and Matter | VII · द्रव्य एवं विकिरण की दोहरी प्रकृति | 3.8% | 3.5 | 1.8 | Practise | NCERT |
| Electromagnetic Induction | IV · विद्युत् चुम्बकीय प्रेरण एवं प्रत्यावर्ती धारा | 3.7% | 2.8 | 2.3 | Practise | NCERT |
| Communication Systems | X · संचार-प्रणालियाँ | 2.9% | 2.0 | 2.0 | Practise | — |
| Electromagnetic Waves | V · विद्युत् चुम्बकीय तरंग | 2.5% | 2.5 | 1.0 | Practise | NCERT |
| Atoms | VIII · परमाणु एवं नाभिक | 2.3% | 1.5 | 1.7 | Practise | NCERT |
| Units and Measurements | Class 11 | 0.2% | 0.3 | 0.0 | — | — |
The board’s unit marks beside what it actually asked
BSEB’s syllabus gives each unit a number of marks out of 70. The last column is what the papers actually printed, 2021–2026. Both put Optics first.
| Unit | इकाई | Syllabus marks (of 70) | Syllabus share | Share of printed marks |
|---|---|---|---|---|
| I. Electrostatics | विद्युत् स्थैतिकी | 8 | 11.4% | 17.1% |
| II. Current Electricity | धारा-विद्युत् | 7 | 10.0% | 9.3% |
| III. Magnetic Effects of Current and Magnetism | विद्युत् धारा के चुम्बकीय प्रभाव एवं चुम्बकत्व | 8 | 11.4% | 13.6% |
| IV. Electromagnetic Induction and Alternating Currents | विद्युत् चुम्बकीय प्रेरण एवं प्रत्यावर्ती धारा | 8 | 11.4% | 12.7% |
| V. Electromagnetic Waves | विद्युत् चुम्बकीय तरंग | 3 | 4.3% | 2.5% |
| VI. Optics | प्रकाशिकी | 14 | 20.0% | 21.4% |
| VII. Dual Nature of Matter and Radiation | द्रव्य एवं विकिरण की दोहरी प्रकृति | 4 | 5.7% | 3.8% |
| VIII. Atoms and Nuclei | परमाणु एवं नाभिक | 6 | 8.6% | 7.4% |
| IX. Electronic Devices | इलेक्ट्रॉनिक युक्तियाँ | 7 | 10.0% | 9.0% |
| X. Communication Systems | संचार-प्रणालियाँ | 5 | 7.1% | 2.9% |
Where they differ: Electrostatics got more than its syllabus share (17.1% against 11.4%); Communication Systems got less than its syllabus share (2.9% against 7.1%).
The syllabus marks come from the board’s printed syllabus booklet, the most recent breakdown we found from the board. Treat them as a guide and the right-hand column as the record.
Year by year
Printed marks per chapter in each paper. There was no paper in 2020 that we could count, and the papers before 2021 were smaller, so compare those years with care.
| Chapter | 2017 | 2018 | 2019 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|---|---|
| Ray Optics and Optical Instruments | 11 | 13 | 22 | 26 | 23 | 23 | 15 | 18 | 22 |
| Current Electricity | 13 | 6 | 12 | 10 | 17 | 11 | 8 | 14 | 18 |
| Electric Charges and Fields | 8 | 9 | 7 | 13 | 13 | 13 | 12 | 15 | 12 |
| Alternating Current | 3 | 1 | 13 | 14 | 15 | 10 | 10 | 11 | 16 |
| Semiconductor Electronics | 8 | 9 | 9 | 14 | 6 | 16 | 17 | 7 | 16 |
| Electrostatic Potential and Capacitance | 3 | 10 | 11 | 16 | 7 | 12 | 16 | 9 | 6 |
| Magnetism and Matter | 4 | 4 | 3 | 14 | 21 | 7 | 11 | 8 | 4 |
| Wave Optics | 3 | 8 | 3 | 5 | 11 | 9 | 9 | 11 | 8 |
| Moving Charges and Magnetism | 2 | 5 | 7 | 4 | 11 | 10 | 11 | 9 | 4 |
| Nuclei | 5 | 4 | 3 | 11 | 7 | 8 | 5 | 7 | 5 |
| Dual Nature of Radiation and Matter | 3 | 2 | 1 | 1 | 3 | 4 | 3 | 13 | 8 |
| Electromagnetic Induction | 0 | 5 | 3 | 1 | 2 | 4 | 13 | 8 | 3 |
| Communication Systems | 3 | 1 | 2 | 4 | 0 | 4 | 5 | 4 | 7 |
| Electromagnetic Waves | 2 | 2 | 3 | 1 | 4 | 4 | 3 | 3 | 6 |
| Atoms | 2 | 1 | 2 | 5 | 0 | 4 | 2 | 3 | 5 |
| Units and Measurements | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |
| Total printed | 70 | 80 | 101 | 140 | 140 | 140 | 140 | 140 | 140 |
Asked almost every year
The same idea, not always in the same words, came up in at least 5 of the 9 papers for each of these 14. If you are short of time, these are the questions to be ready for.
| What is asked | Chapter | Papers | Years | |
|---|---|---|---|---|
| Defects of vision and their correction | Ray Optics and Optical Instruments | 7 of 9 | 2017, 2018, 2019, 2021, 2024, 2025, 2026 | Practise |
| Power factor definition | Alternating Current | 6 of 9 | 2019, 2021, 2022, 2024, 2025, 2026 | Practise |
| Charge density definitions and units | Electric Charges and Fields | 6 of 9 | 2019, 2021, 2022, 2023, 2024, 2025 | Practise |
| Step-up and step-down transformer relations | Alternating Current | 6 of 9 | 2019, 2021, 2022, 2023, 2025, 2026 | Practise |
| Focal length of a lens immersed in a liquid | Ray Optics and Optical Instruments | 6 of 9 | 2017, 2018, 2019, 2022, 2023, 2025 | Practise |
| Rainbow formation and primary versus secondary rainbow | Ray Optics and Optical Instruments | 6 of 9 | 2019, 2021, 2022, 2023, 2024, 2026 | Practise |
| Electric field intensity definition, unit and dimensions | Electric Charges and Fields | 5 of 9 | 2021, 2022, 2023, 2024, 2025 | Practise |
| Electric field of conductors, sheets and spheres | Electric Charges and Fields | 5 of 9 | 2017, 2018, 2024, 2025, 2026 | Practise |
| Flux through a closed surface enclosing charge | Electric Charges and Fields | 5 of 9 | 2018, 2019, 2023, 2024, 2025 | Practise |
| Equivalent focal length or power of lenses in contact | Ray Optics and Optical Instruments | 5 of 9 | 2019, 2022, 2023, 2024, 2025 | Practise |
| Relation between electric field and potential | Electrostatic Potential and Capacitance | 5 of 9 | 2017, 2019, 2021, 2024, 2026 | Practise |
| Prism deviation and refractive index formula | Ray Optics and Optical Instruments | 5 of 9 | 2017, 2018, 2019, 2022, 2026 | Practise |
| Power of accommodation and eye basics | Ray Optics and Optical Instruments | 5 of 9 | 2018, 2021, 2022, 2024, 2025 | Practise |
| Electrical power and energy expressions | Current Electricity | 5 of 9 | 2017, 2019, 2021, 2025, 2026 | Practise |
Questions set again word for word
28 questions appeared in more than one paper with the same wording. Bihar Board sets several versions of each paper and we count one a year, so the real number is higher.
| Question | Part | Years |
|---|---|---|
| What is Lorentz force? | Written | 2019, 2022, 2026 |
| The unit of reactance is | Objective | 2017, 2024 |
| The resistance of ideal ammeter is | Objective | 2019, 2022 |
| Power of electric circuit is | Objective | 2021, 2025 |
| Cathode rays are group of | Objective | 2024, 2026 |
| S.I. unit of electric flux is | Objective | 2021, 2026 |
| The direction of propagation of electromagnetic wave is | Objective | 2019, 2021 |
| The dielectric constant of water is | Objective | 2021, 2026 |
| Capacity of any condenser does not depend upon | Objective | 2024, 2025 |
| S.I unit of pole strength is | Objective | 2017, 2022 |
| Relative permeability is equal to | Objective | 2022, 2026 |
| Nickel is | Objective | 2023, 2026 |
| A convex lens is dipped in a liquid, whose refractive index is equal to refractive index of material of lens. Then its focal length will | Objective | 2018, 2025 |
| To remove hyper metropia lens used is | Objective | 2018, 2026 |
| Which of the following is not electromagnetic wave ? | Objective | 2022, 2025 |
| Boolean expression for NAND gate is | Objective | 2017, 2019 |
| Diode is used as | Objective | 2017, 2023 |
| The solar spectrum is | Objective | 2019, 2026 |
| The wave front due to a point source at a finite distance from the source is | Objective | 2019, 2026 |
| Explain electrical resonance. | Written | 2021, 2025 |
| What is wattless current ? | Written | 2024, 2026 |
| Describe the two shortcomings of Bohr model of atom. | Written | 2019, 2023 |
| Define volume density of charge. Write its S.I. unit. | Written | 2021, 2025 |
| Write properties of diamagnetic, paramagnetic and ferromagnetic materials. | Written | 2021, 2024 |
| What do you mean by power of accommodation of eye? | Written | 2021, 2025 |
| Write necessary conditions for total internal reflection of light. | Written | 2021, 2025 |
| Differentiate between primary and secondary rainbows. | Written | 2023, 2026 |
| Mention the defects of human vision and describe the method to remove them. | Written | 2024, 2026 |
A chapter CBSE dropped but Bihar Board still asks
NCERT removed Communication Systems from its Class 12 book, so CBSE students no longer study it. Bihar Board still lists it as a unit worth 5 marks, and it was asked in 5 of the 6 papers from 2021 to 2026, with 7 printed marks in 2026. Do not skip it because an online list built for CBSE leaves it out. Practise
2 objective questions (2021, 2023) came from Units and Measurements, a Class 11 chapter. That is rare enough to ignore when planning.
Practise with the real papers
- The 2026 paper as a full test: all three parts, timed.
- The 2026 objective section only: the 70 OMR questions.
- Every Bihar Board Class 12 paper we have, as full tests and objective sections.
How we counted
- Papers: 2017, 2018, 2019, 2021, 2022, 2023, 2024, 2025, 2026. One version (set) a year.
- Not counted: no 2015 or 2016 paper online; no 2020 paper.
- Marks are the marks printed against each question, choices included, so a year adds up to 140, not 70 (smaller before 2021).
- Chapters: each question is filed under one chapter, its main one. A random 60 questions from 2021–2026 were checked by hand against their chapter: 58/60 were right.
- Counted on 2026-10-29. When the 2027 paper is out, every number here is recounted.