ISC Class 12 Science Chapter Weightage 2026-27
Subject-wise Marks Distribution & Important Topics
Understand the chapter-wise weightage for ISC Class 12 Science board exams. Focus on high-weightage topics to maximize your scores. Your complete guide to ISC Class 12 Science chapter weightage.
4 Core Subjects
70+30/80+20 Pattern
High Weightage Topics
Updated for 2026-27
ISC Class 12 Physics Chapter Weightage
| Unit / Chapter | Weightage (%) | Marks (Out of 70) | Importance |
|---|---|---|---|
| Electrodynamics | 30% | 21 | Critical |
| Optics | 20% | 14 | Critical |
| Modern Physics | 20% | 14 | High |
| Thermodynamics & Waves | 15% | 10.5 | High |
| Mechanics | 15% | 10.5 | Medium |
Key Topics: Electrodynamics (30%), Optics (20%), Modern Physics (20%)
ISC Class 12 Chemistry Chapter Weightage
Physical Chemistry
| Chapter | Weightage (%) | Marks |
|---|---|---|
| Solutions | 10% | 7 |
| Electrochemistry | 10% | 7 |
| Chemical Kinetics | 10% | 7 |
| Surface Chemistry | 5% | 3.5 |
Inorganic Chemistry
| Chapter | Weightage (%) | Marks |
|---|---|---|
| Coordination Compounds | 10% | 7 |
| d-Block Elements | 10% | 7 |
| f-Block Elements | 5% | 3.5 |
Organic Chemistry
| Chapter | Weightage (%) | Marks |
|---|---|---|
| Haloalkanes and Haloarenes | 10% | 7 |
| Alcohols, Phenols, Ethers | 10% | 7 |
| Aldehydes, Ketones, Carboxylic Acids | 10% | 7 |
| Amines & Biomolecules | 10% | 7 |
ISC Class 12 Mathematics Chapter Weightage
| Unit / Chapter | Weightage (%) | Marks (Out of 80) | Importance |
|---|---|---|---|
| Calculus | 35% | 28 | Critical |
| Algebra | 30% | 24 | Critical |
| Coordinate Geometry | 20% | 16 | High |
| Trigonometry | 10% | 8 | Medium |
| Statistics | 5% | 4 | Medium |
Key Topics: Calculus (35%), Algebra (30%), Coordinate Geometry (20%)
ISC Class 12 Biology Chapter Weightage
| Unit / Chapter | Weightage (%) | Marks (Out of 70) | Importance |
|---|---|---|---|
| Genetics and Evolution | 30% | 21 | Critical |
| Animal Physiology | 25% | 17.5 | Critical |
| Plant Physiology | 15% | 10.5 | High |
| Biotechnology | 15% | 10.5 | High |
| Ecology and Environment | 15% | 10.5 | High |
Key Topics: Genetics and Evolution (30%), Animal Physiology (25%), Biotechnology (15%), Ecology (15%)
Quick Reference: Subject-wise Weightage
| Subject | High Weightage Topics | Approx. Marks |
|---|---|---|
| Physics | Electrodynamics (30%), Optics (20%), Modern Physics (20%) | 49/70 |
| Chemistry | Physical Chemistry (35%), Organic Chemistry (35%), Inorganic Chemistry (30%) | 49/70 |
| Mathematics | Calculus (35%), Algebra (30%), Coordinate Geometry (20%) | 68/80 |
| Biology | Genetics and Evolution (30%), Animal Physiology (25%), Biotechnology (15%), Ecology (15%) | 42/70 |
Final Tip: Prioritize high-weightage chapters first. Master them thoroughly before moving to other chapters. This strategy will help you score well in both board exams and competitive exams.
Frequently Asked Questions
Chapter weightage helps you prioritize your study time. Focus more on high-weightage chapters to maximize your scores in board exams.
The weightage pattern is set by CISCE and is generally consistent across all ISC schools. However, minor variations may exist. Always check with your school for the exact distribution.
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