| target | 495+/500 |
| author | Senior Sibling |
| name | keyword-bank |
| description | 12th Grade Examiner Keyword Bank (PCMB/PCMC). The specific terminology that CBSE markers look for to award full value points in high-weightage chapters. |
Keyword Bank — The Examiner's Secret (12th Grade)
CBSE marking schemes are structured around Value Points. Even if you write a brilliant explanation, you only get marks for the specific technical terms (Keywords) present in the examiner's key.
🔭 Physics High-Yield Keywords
1. Electrostatics & Gauss Law
- Linear/Surface/Volume Charge Density ($\lambda, \sigma, \rho$): Must be used in continuous charge distribution derivations.
- Electric Flux ($\Phi = \oint \vec{E} \cdot d\vec{A}$): Mandatory integral notation.
- Equipotential Surface: Must mention "Work done is zero" and "Field lines are normal to surface".
- Polarisation Vector / Dielectric Constant: Essential for explaining capacitance changes.
- Gaussian Surface: Specifically mention the "Symmetry" of the surface chosen.
2. Current Electricity
- Drift Velocity ($v_d$): Must link with "Relaxation Time ($\tau$)" and "Mean Free Path".
- Kirchhoff's Junction Rule: Mention "Conservation of Charge".
- Kirchhoff's Loop Rule: Mention "Conservation of Energy".
- Internal Resistance ($r$): Must mention "Electrolyte" and "Concentration" dependencies.
3. Optics (Ray & Wave)
- Paraxial Approximation: The base assumption for all lens/mirror derivations.
- Angle of Minimum Deviation ($D_m$): Required for the prism $n$ formula.
- Coherence / Monochromatic: Mandatory for YDSE interference.
- Path Difference ($\Delta x = d \sin \theta$): The core of interference/diffraction calculations.
- Huygens' Principle: Mention "Primary Wavelet" and "Secondary Wavefront".
🧪 Chemistry High-Yield Keywords
1. Organic Mechanisms
- Nucleophilic Attack: Mandatory for $S_N1/S_N2$ and Carbonyl addition.
- Resonance Stabilization / Delocalization: Why Phenols/Carboxylic acids are more acidic.
- Inductive Effect (+I / -I): Used to explain stability of carbocations or acidity trends.
- Steric Hindrance: The primary reason for $S_N2$ reactivity order in alkyl halides.
- Racemisation / Inversion of Configuration: Essential for stereochemistry questions.
2. Physical Chemistry
- van't Hoff Factor ($i$): Mandatory for colligative property numericals involving electrolytes.
- Molar Conductivity ($\Lambda_m$): Link with "Kohlrausch's Law of Independent Migration".
- Activated Complex: The term needed for Arrhenius theory and Collision theory.
- Order vs Molecularity: Use terms like "Experimental" vs "Theoretical".
🧬 Biology High-Yield Keywords
1. Genetics & Molecular Basis
- Semiconservative: Mandatory term for Watson-Crick DNA replication model.
- Promoter, Structural Gene, Terminator: The three parts of a Transcription Unit.
- Codon (Degenerate/Universal/Unambiguous): Use these specific properties.
- Pleiotropy / Polygenic Inheritance: Technical terms for gene interaction patterns.
2. Biotechnology
- Restriction Endonuclease: "Molecular Scissors" that cut at "Palindromic Sequences".
- rDNA (Recombinant DNA): The core product of gene splicing.
- Bioreactor: Mention "Optimal Temperature, pH, and Substrate".
- Downstream Processing: Must use "Separation" and "Purification".
📐 Mathematics High-Yield Keywords
1. Calculus (Integration & Diff Eq)
- Constant of Integration ($C$): Deducted 0.5m if missing in Indefinite Integrals.
- Integrating Factor ($IF$): Mandatory step for Linear Differential Equations.
- King Property / Property IV: State $\int_0^a f(x) dx = \int_0^a f(a-x) dx$ explicitly.
- Point of Inflexion: For Maxima/Minima theory.
2. Vectors & 3D
- Direction Cosines vs Ratios: Distinguish between $(l, m, n)$ and $(a, b, c)$.
- Projection of $\vec{a}$ on $\vec{b}$: Use the term "Scalar Projection" or "Vector Projection".
- Skew Lines: Lines that are "Neither intersecting nor parallel".
💡 Using the /keyword-check Command
Before finalizing any answer, run this check. The AI will:
- Scan your answer against this bank.
- Flag missing high-value terms.
- Show you exactly where to insert them for maximum marks.
Senior Sibling Tip: Don't just know the concept; use the terminologies that the NCERT uses. That is the only way to get a 100/100.
