CBSE Class 12 Physics Electromagnetic Induction 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), 1-2 numericals/derivations on induced emf & inductance (3-5 marks), occasional case-based.
Repeated Topics: Faraday’s laws of EMI, Lenz’s law (direction of induced current), motional emf (rod moving in B-field), self & mutual inductance, energy stored in inductor, eddy currents & applications (damping, braking), AC generator (emf equation), flux linkage, growth/decay in LR circuit (rare).
Difficulty: Medium; motional emf numericals & Lenz’s law applications are most repeated & scoring.
Changes: More numericals on motional emf with rotating rod/loop & energy in inductor in 2023–2025.

Most Important and Repeated Questions

Question Example	Type/Marks	Years Repeated	Notes
State Faraday’s laws of electromagnetic induction. Explain Lenz’s law and how it follows conservation of energy. Give examples.	Short Answer/Theory (3 marks)	2021, 2022, 2023, 2024, 2025	Repeated 5x; ε = -dΦ/dt; Lenz: induced current opposes change → mechanical work done = electrical energy.
A conducting rod of length l moves with velocity v perpendicular to uniform magnetic field B. Derive motional emf and find induced current if resistance R.	Derivation/Numerical (3-4 marks)	2021 Term 2, 2022, 2023, 2024	Repeated 4x; ε = B l v, I = B l v / R; direction by Fleming’s right-hand rule.
Define self-inductance and mutual inductance. Derive expression for energy stored in an inductor (1/2 LI²).	Derivation (3 marks)	2022, 2023, 2024, 2025	Repeated 4x; L = Φ/I; Power = LI dI/dt → energy U = ∫ L I dI = (1/2) L I².
Assertion: Induced emf always opposes the change in magnetic flux. Reason: Lenz’s law is a consequence of conservation of energy.	Assertion-Reason (1 mark)	2023, 2024, 2025	Repeated 3x; Both true, reason explains.
A coil rotates in uniform magnetic field with angular velocity ω. Derive expression for induced emf in AC generator.	Derivation (3 marks)	2021 Term 1, 2022, 2023, 2025	Repeated 4x; Φ = N B A cos(ωt), ε = -dΦ/dt = N B A ω sin(ωt) = ε₀ sin(ωt).
Calculate induced emf in a loop when magnetic field changes or area changes (e.g., rod sliding on rails).	Numerical (3 marks)	2022, 2023, 2024	Repeated 3x; ε = B l v or B A dB/dt or B dA/dt.
MCQ: The direction of induced current is given by: (a) Fleming’s left-hand rule (b) right-hand rule (c) Lenz’s law (d) Ampere’s law	MCQ (1 mark)	2021 Term 1, 2023, 2024	Repeated 3x; Answer (c) Lenz’s law (or Fleming’s right-hand rule for direction).
Explain eddy currents. Give methods to reduce eddy current loss (lamination, high resistivity material).	Short Answer (2-3 marks)	2023, 2025	Repeated 2x; Induced currents in bulk conductor → heating loss → use thin sheets/insulation.
Case-based: Given changing flux through loop/rod moving in B-field, find induced emf/current & direction.	Case-Based (4 marks)	2023, 2025	Repeated 2x; Use Faraday + Lenz → direction opposes change.
Find self-inductance of a solenoid or mutual inductance of two coils.	Short Answer (2 marks)	2021 Term 2, 2024	Repeated 2x; Solenoid L = μ₀ n² A l; Mutual M = μ₀ n1 n2 A l.

Best Format for Preparation and Answering

Study Format: Memorize Faraday’s & Lenz’s laws with examples. Practice motional emf numericals (rod on rails, rotating loop) & inductance formulas daily. Draw flux change diagrams.
Answer Format: Derivations: Show flux Φ → ε = -dΦ/dt → direction by Lenz. Numericals: Calculate dΦ/dt or B l v → include sign/direction. Always mention conservation of energy with Lenz.
Tips: Motional emf (rod moving in B) & AC generator emf are highest repeat & marks. Always determine direction using Lenz’s law. Time: 8–10 mins for 3–5 mark questions. Very scoring if direction & units are correct.

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