NEET Physics-05 Magnetism, Induction and Electromagnetic Waves

Imagine being able to predict the direction of a magnetic field just by curling your fingers—and then turn that idea into real calculations. Starting with the magnetic effects of current, you’ll learn to apply the Biot–Savart law to a circular loop, compare its inverse-square structure to Coulomb’s law, and use the right-hand thumb rule to keep directions straight. You’ll work out the field at the center of a loop \(\,B=\mu_0 I/2R\,\) (and for \(N\) turns), the on-axis field, and even the field of a current-carrying arc. Next, Ampère’s circuital law makes symmetry your shortcut: derive \(B=\mu_0 I/2\pi r\) around a long straight wire, get \(B=\mu_0 nI\) inside a solenoid, and avoid common traps with finite wires. You’ll connect fields to forces through the Lorentz force \(\mathbf{F}=q(\mathbf{E}+\mathbf{v}\times\mathbf{B})\), circular and helical motion, and the velocity selector \(v=E/B\). From there, calculate forces between parallel currents (and the ampere definition), torque on a current loop, magnetic dipole moment, and galvanometer conversions to ammeter and voltmeter. Electromagnetic induction and AC topics build practical circuit skill: Faraday’s and Lenz’s laws, eddy currents, inductance and energy storage, RMS vs peak values, impedance, resonance, power factor, generators, and transformers. Finally, Maxwell’s displacement current leads into electromagnetic waves and the full spectrum—from radio to gamma rays—with sources and applications.