elektromagnetikmë

Elektromagnetikmë, or electromagnetics, is the branch of physics that studies the interactions between electric charges, currents, and magnetic fields, and the electromagnetic radiation that links them. It unifies electricity, magnetism, and light under a common framework.

The central framework is Maxwell's equations, which describe how charges and currents produce electric and magnetic fields and how these fields propagate and interact with matter. In differential form: ∇·E = ρ/ε0, ∇·B = 0, ∇×E = -∂B/∂t, ∇×B = μ0 J + μ0 ε0 ∂E/∂t. In media, the fields relate through D = εE and B = μH, with ε and μ depending on the material.

Electromagnetic waves are solutions in vacuum that travel at the speed of light, c = 1/√(ε0 μ0). E and B oscillate perpendicular to each other and to the direction of travel. The spectrum spans radio waves to gamma rays, with wavelength and frequency determining interaction with matter via reflection, refraction, absorption, and polarization.

Applications include communications (radio, television, mobile networks, fiber optics), power transmission, imaging and sensing (X-ray, MRI, radar), and a broad range of scientific and engineering technologies. The field also connects classical and quantum descriptions of light, through concepts such as photons in quantum electrodynamics.

Historically, electromagnetism emerged from experiments by Oersted and Faraday and was unified by Maxwell in the 19th century. It is foundational to relativity, with the electric and magnetic fields forming components of the same electromagnetic tensor, and to quantum theory, where light is carried by photons.