CBSE Class 12 Physics: Most Repeated Derivations and Questions — 5-Year Analysis

Most Repeated Derivations (Must Know)

• Lens Maker's Formula — appeared 4/5 years (5 marks)
• Electric field due to dipole (axial and equatorial) — 3/5 years
• Gauss's theorem applications (infinite plane sheet, uniformly charged sphere) — 3/5 years
• Young's Double Slit: fringe width derivation — 3/5 years
• AC Generator principle and working — 3/5 years
• Capacitance of parallel plate capacitor — 2/5 years

Most Repeated Numericals

• Kirchhoff's laws: Wheatstone bridge, potentiometer calculations
• Lens/mirror formula problems: find image, magnification
• EMI: motional EMF, self/mutual inductance
• Electrostatics: force between charges, electric potential
• de Broglie wavelength calculations

Chapter-Wise Marks (Typical)

• Electrostatics: 8-10 marks
• Current Electricity: 7-8 marks
• EMI & AC: 8-10 marks
• Optics (Ray + Wave): 12-14 marks — HIGHEST weightage
• Dual Nature + Atoms + Nuclei: 8-10 marks
• Communication Systems: 2-3 marks

Strategy

• Focus 60% study time on Optics + Electrostatics + EMI (covers ~35 marks)
• Practice derivations by writing them, not just reading
• For numericals: practice 5 problems per chapter minimum
• Know all ray diagrams cold — they are quick marks