CBSE Class 12 Physics Electric Charges and Fields PYQs Analysis (2021-2025)

Based on detailed analysis of last 5 years' papers. Perfect for 2026 Boards prep!

Key Trends

Weightage Breakdown: 1-2 MCQs/assertion-reason (1 mark), 1-2 short answers (2 marks), 1 numerical/proof on Gauss's law or dipole (3-5 marks).
Repeated Topics: Coulomb's law, superposition principle, electric field due to point charge/line/dipole, Gauss's law applications (sphere, cylinder, sheet), electric dipole (torque, potential energy, field on axis/equatorial), electric flux, field lines properties.
Difficulty: Easy to medium; Gauss's law numericals & dipole torque/field are most repeated & scoring.
Changes: More assertion-reason & case-based on field lines/Gauss's law in 2023–2025.

Most Important and Repeated Questions

Question Example	Type/Marks	Years Repeated	Notes
Using Gauss's law, derive electric field due to infinitely long straight uniformly charged wire (or infinite plane sheet / spherical shell).	Derivation (3-4 marks)	2021, 2022, 2023, 2024, 2025	Repeated 5x; Gaussian surface cylinder/plane/sphere → flux = E×area = Q_enclosed/ε₀ → E = λ/(2πε₀r) or σ/(2ε₀) or Q/(4πε₀r²).
Electric dipole moment p is placed in uniform electric field E. Find torque on dipole and potential energy. Also find field on axial & equatorial line.	Short Answer (3 marks)	2021 Term 2, 2022, 2023, 2024	Repeated 4x; τ = pE sinθ, U = -p·E = -pE cosθ; E_axial = 2p/(4πε₀r³), E_equatorial = -p/(4πε₀r³).
Two point charges +q and -q are placed at distance 2a. Find electric field at point on perpendicular bisector at distance r from centre.	Numerical/Short Answer (2-3 marks)	2022, 2023, 2024, 2025	Repeated 4x; Dipole field on equatorial line: E = p/(4πε₀r³) towards -q (p = q×2a).
Assertion: Electric field lines never form closed loops. Reason: Electrostatic field is conservative.	Assertion-Reason (1 mark)	2023, 2024, 2025	Repeated 3x; Both true, reason explains (work zero in closed path).
Calculate electric flux through a cube of side a placed with one face perpendicular to uniform electric field E (or Gaussian surface variants).	Short Answer (2 marks)	2021 Term 1, 2022, 2023, 2025	Repeated 4x; Total flux = 0 (no charge inside) or E a² through one face if field along normal.
Force between two charges q1 and q2 separated by r is F. If separation becomes r/2 in a medium of dielectric constant K, find new force.	Numerical (2 marks)	2022, 2024	Repeated 2x; F' = K (q1 q2)/(4πε₀ (r/2)²) = 4K F (in medium force decreases by K).
MCQ: The SI unit of electric flux is: (a) N m² C⁻¹ (b) V m (c) both (d) none	MCQ (1 mark)	2021 Term 1, 2023, 2024	Repeated 3x; Answer (c) both (N m²/C = V m).
Derive expression for electric field due to dipole at axial point.	Derivation (3 marks)	2023, 2025	Repeated 2x; E = (1/(4πε₀)) (2p / r³) along p for r >> a.
Case-based: Given charge distribution (line/sheet/sphere), apply Gauss's law to find field/flux at given point.	Case-Based (4 marks)	2023, 2025	Repeated 2x; Choose symmetric Gaussian surface → apply Gauss's law.
Two charges +q and +4q are separated by distance d. Find point where electric field is zero.	Short Answer (2 marks)	2021 Term 2, 2024	Repeated 2x; Outside on line joining, closer to smaller charge: distance from +q = d/3 towards +4q.

Best Format for Preparation and Answering

Study Format: Memorize Gauss's law applications (sphere, cylinder, sheet) & dipole formulas table. Practice numericals on field & torque daily. Draw field lines for point charge/dipole/sheet.
Answer Format: Derivations: Draw Gaussian surface → write flux = ∫E·dA = Q/ε₀ → solve for E. Numericals: Show vector form or magnitude + direction. Always include units & direction.
Tips: Gauss's law derivations & dipole torque/field are highest repeat & marks. Practice choosing correct Gaussian surface. Time: 8–10 mins for 3–5 mark questions. Very scoring if steps are clear & diagram neat.

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