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The CBSE Class 12 Physics theory paper is 70 marks: Electrostatics and Current Electricity 16, Magnetic Effects of Current and Magnetism with Electromagnetic Induction and Alternating Currents 17, Electromagnetic Waves and Optics 18, Dual Nature of Radiation and Matter with Atoms and Nuclei 12, and Electronic Devices 7. Optics and the two electricity units together are close to half the paper. Practicals carry the remaining 30.
Last updated: 26 September 2026
Which units carry the most marks?
| Unit | Chapters (NCERT) | Marks |
|---|---|---|
| IβII Β· Electrostatics + Current Electricity | Electric Charges and Fields Β· Electrostatic Potential and Capacitance Β· Current Electricity | 16 |
| IIIβIV Β· Magnetic Effects of Current and Magnetism + EMI and AC | Moving Charges and Magnetism Β· Magnetism and Matter Β· Electromagnetic Induction Β· Alternating Current | 17 |
| VβVI Β· Electromagnetic Waves + Optics | Electromagnetic Waves Β· Ray Optics and Optical Instruments Β· Wave Optics | 18 |
| VIIβVIII Β· Dual Nature of Radiation and Matter + Atoms and Nuclei | Dual Nature of Radiation and Matter Β· Atoms Β· Nuclei | 12 |
| IX Β· Electronic Devices | Semiconductor Electronics | 7 |
| Theory total | 70 | |
| Practical | experiments, activities, project, viva | 30 |
Three unit-pairs β electricity, magnetism and optics β are 51 of the 70 marks. That is the single most useful fact in the table, because it is the opposite of how most students split their time: modern physics and semiconductors feel newer and get more evenings than their 19 marks deserve.
Which of these chapters are costing you marks? The free 15-minute Score Map tests you chapter by chapter and returns the three to fix first. No card.
Which chapters inside those units repeat every year?
Weightage is set per unit, not per chapter, so the board does not publish a chapter split. But the question types recur, and they cluster:
- Ray Optics β lens and mirror numericals, the compound microscope or telescope derivation, total internal reflection. Rarely fewer than 6β8 marks across sections.
- Current Electricity β Kirchhoff’s laws in a circuit, the Wheatstone bridge, drift velocity, the potentiometer or meter-bridge experiment as a case study.
- Moving Charges and Magnetism β force on a conductor, the moving-coil galvanometer and its conversion to ammeter/voltmeter, the cyclotron.
- Electromagnetic Induction and AC β Lenz’s law reasoning, an LCR circuit numerical, the transformer.
- Electrostatics β Gauss’s law applied to a sheet or shell, capacitor combinations, potential energy of a system of charges.
- Dual Nature β the photoelectric equation, stopping potential graphs, de Broglie wavelength.
If you can do the derivations in those six chapters cleanly, with every step written, you have covered the part of the paper where marks are most predictable.
How should a Class 12 student order revision from this table?
Rank chapters by marks against your own confidence, and start where the two disagree most β a heavy chapter you are weak in. For most students that is Ray Optics or Electromagnetic Induction, not Semiconductors.
| Chapter is⦠| What to do | Time share |
|---|---|---|
| Heavy and weak | Start here. Derivations first, then numericals with units written every time. | ~60% |
| Heavy and strong | One timed section from a sample paper to protect the marks. | ~20% |
| Light and weak | After the two rows above β Semiconductors is usually here. | ~20% |
| Light and strong | Leave it. | 0% |
The half-mark that goes missing. The marking scheme for Physics pays separately for the formula, the substitution, the working and the final answer with its SI unit. A correct answer without the unit loses the last mark; a wrong final answer with correct method keeps most of the rest. Since 2026, Class 12 answer books are marked on screen β so every step also has to be legible on a scan. We mark a real answer this way, live, on Saturday 3 October at 6 PM.
What does this table not tell you?
It does not tell you the chapter split inside a unit β the board sets that each year within the unit total. It does not tell you which sections the marks will sit in; the 2026-27 sample paper does that, and it is worth reading once for structure alone. And it does not tell you which chapters are weak for you. A weightage table is a map of where marks live; only a diagnostic tells you where yours are leaking.
Frequently asked questions
How many marks is the Class 12 Physics theory paper?
70. Practicals carry 30, and you must pass theory and practicals separately.
Which unit has the highest weightage in Class 12 Physics?
Electromagnetic Waves and Optics together, at 18 marks; Magnetism with EMI and AC is 17; Electrostatics with Current Electricity is 16.
Is Semiconductors important for the board exam?
It carries 7 marks β real, but the smallest unit. Do it after the electricity, magnetism and optics chapters are solid.
Does CBSE publish chapter-wise weightage?
No, only unit-wise. Chapter-wise lists online are estimates from past papers.
Has the Class 12 Physics syllabus changed for 2026-27?
No major change has been announced; check the current curriculum PDF on cbseacademic.nic.in for your year’s exact unit list.
Where can I practise a real Physics board paper?
The 2026-27 sample paper and marking scheme are on cbseacademic.nic.in. On myAiSchool you can sit real board papers and be marked against the scheme, step by step.
Find your weak chapters in 15 minutes. The free Score Map for Class 12 Physics tests four chapters, five questions each, and returns the three to fix first.