Most Tested Topics (NEET 2018–2024)
1. Motional EMF — ε = Bvl (Almost Every Year) Questions calculate EMF for a moving rod, or ask for the force/power required to maintain motion. Key: always check if v, B, l are perpendicular. Power dissipated = Fv = R (energy conservation check).
2. Lenz's Law Direction (Every 2 Years) Given a scenario (magnet approaching/receding, flux increasing/decreasing), identify induced current direction. Method: identify change in flux direction → induced field must oppose → use right-hand rule for current direction.
3. LCR Series Circuit (NEET 2020, 2023, 2024) Calculate Z, I_rms, power factor, average power. Standard trap: forgetting to compute X_L and X_C separately before finding net reactance. Always use P = I_r R as a cross-check.
4. Resonance Properties (NEET 2021, 2023) Conceptual: Z = R at resonance (NOT zero); I is maximum; φ = 0; power factor = 1; V_L = V_C (but individually may exceed supply). Numerical: find f_{0} = 1/(2π√LC).
5. Transformer (NEET 2019, 2022, 2024) Find turns ratio, calculate secondary voltage/current, compute efficiency. Most common error: using N_s/N_p for current ratio instead of N_p/N_s. With efficiency: P_p = P_s/η; I_p = P_p/V_p (actual > ideal).
6. Wattless Current / Power Factor (Every 3 Years) Why does a pure inductor/capacitor consume zero power? Answer: phase difference φ = 90°, cos 90° = 0. Energy stored and returned each half-cycle.
Prediction for NEET 2026
High probability topics based on gap analysis: Motional EMF (calculation), LCR resonance (numerical), Transformer (multi-step), Lenz's law (conceptual direction). Medium probability: Energy stored in inductor, mutual inductance, RMS vs mean value comparison.
Exam Strategy
- For direction questions: draw a rough sketch, mark flux direction, apply Lenz's law.
- For numericals: always write given data with units, convert to SI, then apply formula.
- For transformer: write V ratio and N ratio first; derive I ratio as inverse.