Class‑12 CBSE – Physics
Moving Charges & Magnetism
(A comprehensive, exam‑oriented study guide for IIT‑JEE/Competitive exams)
Key Concepts
• Lorentz force on a moving charge
• Magnetic field of currents (Biot‑Savart & Ampère’s law)
• Magnetic flux, Faraday’s law, Lenz’s law
• Motional EMF, self‑ and mutual inductance
• Energy stored in magnetic fields
• Practical problems – motors, generators, transformers
1. Introduction
When a charge moves through a magnetic field, it experiences a force that is perpendicular to both its velocity and the magnetic field.
The study of moving charges in magnetic fields underpins many modern technologies (motors, generators, inductors, transformers, etc.).