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Class 12 starts fast. Within weeks you are calculating electric fields, naming organic compounds and integrating functions, while the board exam already feels close. Many students find that Class 12 is not harder because the ideas are new, but because it quietly assumes Class 11 tools they never secured. This post uses the CBSE 2026-27 curriculum to show what shifts in each subject, works one example that joins the two years, and ends with a plan for your first months.
How does the weight shift between the two years?
The CBSE senior secondary curriculum documents for 2026-27 give unit-wise marks for each class. Always check the version for your own exam year on cbseacademic.nic.in, because weights and deleted portions change.
Physics. The physics curriculum gives 70 theory marks and 30 practical marks in both years. In Class 11, kinematics, laws of motion and measurement carry 23 marks together, and mechanics continues through work, rotation and gravitation. In Class 12 the groups are electrostatics and current electricity (16), magnetism, induction and AC (17), electromagnetic waves and optics (18), dual nature, atoms and nuclei (12) and electronic devices (7).
Chemistry. The chemistry curriculum also has 70 theory marks. In Class 12, solutions, electrochemistry and chemical kinetics carry 7 + 9 + 7 = 23 marks; d- and f-block elements and coordination compounds 7 + 7 = 14; and the five organic units from haloalkanes to biomolecules 6 + 6 + 8 + 6 + 7 = 33.
Maths. The maths curriculum has 80 marks for the paper and 20 for internal assessment. In Class 11, calculus is 8 of the 80 marks. In Class 12 it is 35, covering continuity and differentiability, applications of derivatives, integrals, applications of integrals and differential equations.
What changes in physics, and what does it need from Class 11?
Class 12 physics changes topic but not toolkit. Electric potential energy is the work-energy theorem applied to a new force. Magnetic force on a moving charge needs vector cross products and circular motion. Wave optics needs the wave ideas from Class 11 oscillations and waves. If those chapters are weak, Class 12 will feel like memorising formulas.
Worked example: Class 11 work-energy in a Class 12 problem
Question: two point charges, q1 = 2 µC and q2 = 3 µC, are 0.30 m apart. How much work is needed to bring them to 0.10 m apart? Take k = 9 × 10^9 N m² C^-2.
Potential energy at the start. U = kq1q2 / r. First kq1q2 = 9 × 10^9 × (2 × 10^-6) × (3 × 10^-6) = 9 × 10^9 × 6 × 10^-12 = 0.054 N m². So U1 = 0.054 / 0.30 = 0.18 J.
Potential energy at the end. U2 = 0.054 / 0.10 = 0.54 J.
Work needed. From Class 11, the work done by an external agent moving a system slowly equals the change in potential energy: W = U2 − U1 = 0.54 − 0.18 = 0.36 J.
Check the sign. Both charges are positive and repel, so pushing them closer should need positive work. It does.
The common mistakes are Class 11 mistakes: forgetting that µ means 10^-6, squaring r as if this were a force, and losing track of who does the work. Our post on electrostatics mistakes goes through more of these.
What changes in chemistry?
Class 12 chemistry is heavier on organic chemistry, at 33 of 70 theory marks. Those units build directly on Class 11's "Organic Chemistry: Some Basic Principles and Techniques" (11 marks) and "Hydrocarbons" (10 marks), where the curriculum covers nomenclature, isomerism and the fundamental concepts of reaction mechanism. Physical chemistry in Class 12 leans on the Class 11 mole concept and equilibrium: solutions needs molarity and molality, and electrochemistry needs redox. If you cannot convert moles to grams quickly, every concentration problem will slow you down.
What changes in maths?
The jump in calculus is the largest single change. Class 11 introduces limits and derivatives, with the derivative described as a rate of change and as the slope of a tangent. Class 12 then spends 35 marks on what you can do with that idea. Integration in particular depends on trigonometric identities from Class 11 and on fluent algebra. Students who struggle with integration usually struggle with the identity or the substitution, not with the idea of an integral.
What mistakes do students make in the transition?
Treating Class 11 as finished. The Class 12 theory syllabus lists only Class 12 units, but those units use Class 11 tools in almost every question.
Ignoring practicals. Physics and chemistry each give 30 marks to practical work, and maths gives 20 to internal assessment. These are steady marks that need regular effort through the year.
Saving revision for the end. In the review by Dunlosky and colleagues (2013), practice testing and distributed practice were the two techniques rated high in utility, while rereading and highlighting did not consistently help.
A plan for your first months of Class 12
Week 1: list the Class 11 tools each subject needs: vectors and work-energy for physics, the mole and organic basics for chemistry, trigonometry and derivatives for maths.
Weeks 2 to 4: spend about 30 minutes a day revising one tool, with 10 problems each, alongside new Class 12 chapters.
From month 2: every Sunday, take a short mixed test from both years.
All year: keep your practical record and investigatory project up to date.
If you are not sure which Class 11 gaps matter most, start from what you can and cannot do. Fermi's AI tutor can work out what you already know and build a plan for the session, so each revision hour begins with a clear next step. For subject plans later in the year, see our Class 12 physics strategy and board revision plan.
This week, open your Class 11 vectors chapter and solve five problems before your next Class 12 physics class.
