Electromagnetism

Electrostatics, potential and capacitance, currents, magnetostatics, induction, and Maxwell’s equations with electromagnetic waves.

Classical electromagnetism is the theory of the electric and magnetic fields and their sources. It builds in a fixed order: the field of charges at rest, the energy they store, the currents they make when set in motion, the magnetic field those currents produce, the coupling that appears when the fields change in time, and finally Maxwell’s completed equations — whose empty-space solutions are light itself. The waves that result carry the general properties studied in the waves chapter.

• 11.1 Electrostatics: Coulomb’s law and Gauss’s law — the field of a point charge, superposition, and the field of symmetric distributions.
• 11.2 Potential, capacitance, and electric energy — the electric potential, the parallel-plate capacitor, and energy in the field.
• 11.3 Current, resistance, and Ohm’s law — current density, drift and mobility, and the microscopic origin of Ohm’s law.
• 11.4 Magnetostatics: the field of steady currents — the Lorentz force, $\nabla\cdot\mathbf{B}=0$, and Ampère’s and Biot–Savart laws.
• 11.5 Faraday’s law and electromagnetic induction — changing flux, Lenz’s law, and the coupling of the fields.
• 11.6 Maxwell’s equations and electromagnetic waves — the displacement current, the complete equations, and light as an electromagnetic wave.