elektromagnetika

Elektromagnetika is the branch of physics that studies the interactions between electric charges, electric currents, and the accompanying electric and magnetic fields. It covers static electricity and magnetism as well as the propagation of electromagnetic radiation through space and matter. The theory unifies electricity, magnetism and optics into a single framework.

The foundational principles are encapsulated in Maxwell's equations, which describe how charges and currents generate electric and magnetic fields and how changing fields propagate as waves. In addition to these field equations, the motion of charges in fields is described by the Lorentz force law, F = q(E + v × B). A key consequence is that changing electric and magnetic fields propagate disturbances at the speed of light, c, linking electromagnetism to the nature of light.

Electromagnetic phenomena span a wide range of frequencies and wavelengths, from static fields (DC) to radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays. The interaction of EM waves with matter explains reflection, refraction, absorption, polarization and diffraction, providing the basis for optics and photonics.

Applications of electromagnetism are vast and include electrical power generation and transmission, electric motors and transformers, wireless communication, radar, imaging techniques such as MRI and X-ray, and many electronic devices. The field also underpins modern theories in physics, including quantum electrodynamics, which describes how light and matter interact at the quantum level.

Historically, experiments by Coulomb, Oersted, Faraday and others led to the formulation of the underlying laws, while James Clerk Maxwell unified electricity, magnetism and optics in the 19th century and predicted the existence of electromagnetic waves.