Electromagnetism

Classical electromagnetic field theory: charges, currents, Maxwell's laws, and radiation.

General idea of the topic

Electromagnetism studies how electric charges at rest and in motion generate fields, forces and waves that transport energy and information. Maxwell's unified framework connects electrostatics, magnetism, induction and radiation under a coherent set of field equations. The goal is to model electromagnetic interactions with physical judgment, identify the domain of validity of each approximation and solve problems with full traceability.

What you will truly understand

  • How a charge distribution generates an electric field and how currents generate a magnetic field.
  • How time-varying fields induce complementary fields and produce electromagnetic waves.
  • How to design and analyze electric circuits in both direct and alternating current.
  • How light behaves as an electromagnetic wave at interfaces, lenses and optical systems.
  • How to move from equations to physical interpretation, dimensional validation and experimental reading.

Recommended learning route

  1. Fundamentals: charge, field, force and superposition as the foundation of the entire block.
  2. Electrostatics: field, potential, energy, Gauss and applications in capacitors.
  3. Electric current: intensity, resistance, Ohm, Kirchhoff and DC circuits.
  4. Magnetism: magnetic field, sources, magnetic forces and materials.
  5. Electromagnetic induction: Faraday, Lenz, inductance and applications.
  6. Alternating current: impedance, reactance, resonance and AC power.
  7. Electromagnetic waves: propagation, spectrum, energy and momentum.
  8. Optics: geometrical (rays, lenses, mirrors) and physical (interference, diffraction, polarization).

Physical criterion you must acquire

Choose the model by symmetry, scale and temporal regime before operating. Distinguish the static regime from the quasi-static and the wave regime. Verify units, signs and vector coherence at every step. Do not confuse field with potential or force with energy.

Connection with real problems

  • Domestic electricity, distribution networks and protections.
  • Electronics, telecommunications and signal processing.
  • Motors, generators, transformers and power systems.
  • Optical fiber, imaging instruments and metrology.
  • Medical diagnostics, industrial sensors and quality control.

Final goal of the topic

Solve electromagnetism problems independently: choose the appropriate model, justify its hypotheses, calculate with dimensional coherence and interpret the result as a verifiable physical statement.

Topics in this section

  • Fundamentals (Electromagnetism)

    Electric charge conservation, quantization, and foundational electromagnetic vector principles.

  • Electrostatics

    Electrostatic fields generated by stationary charge distributions in vacuum and dielectrics.

  • Electric Current (Electromagnetism)

    Drift of electric charges, current density, resistance, conductivity, and Joule heating.

  • Alternating Current

    Sinusoidal AC voltage generation, root-mean-square values, and complex RLC circuit impedance.

  • Maxwell's Equations

    Unified synthesis of classical electrodynamics through Maxwell's four fundamental equations.

  • Electromagnetic Waves (Electromagnetism)

    Generation, polarization, and propagation of electromagnetic waves at the speed of light.

  • Optics

    Classical geometrical and wave optics: light propagation, lenses, mirrors, and interferometry.

  • Household Electricity

    Residential electrical distribution, single and three-phase wiring, circuit breakers, and load.

  • Magnetism

    Magnetic interactions, dipoles, magnetic permeability of materials, and ferromagnetic domains.

  • Electromagnetic Induction

    Faraday's law of induction, Lenz's rule, induced electromotive force, and eddy currents.