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The electromagnetic field is described by classical electrodynamics, an example of a classical field theory. This theory describes many macroscopic physical phenomena accurately. [6] However, it was unable to explain the photoelectric effect and atomic absorption spectroscopy, experiments at the atomic scale.
The theory provides a description of electromagnetic phenomena whenever the relevant length scales and field strengths are large enough that quantum mechanical effects are negligible. For small distances and low field strengths, such interactions are better described by quantum electrodynamics which is a quantum field theory .
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
Dudley DG, Mathematical Foundations for Electromagnetic Theory, Wiley-IEEE, 1994. [159] [242] Hanson GW, Yakovlev AB, Operator Theory for Electromagnetics: An Introduction, Springer, 2002. [243] Idemen MM, Discontinuities in the Electromagnetic Field, Wiley-IEEE, 2011. [244]
A theory of electromagnetism, known as classical electromagnetism, was developed by several physicists during the period between 1820 and 1873, when James Clerk Maxwell's treatise was published, which unified previous developments into a single theory, proposing that light was an electromagnetic wave propagating in the luminiferous ether. [26]
This theory can be extended, at least as a classical field theory, to curved spacetime. This arises similarly to the flat spacetime case, from coupling a free electromagnetic theory to a free fermion theory and including an interaction which promotes the partial derivative in the fermion theory to a gauge-covariant derivative.
Maxwell's theory of electromagnetism describes the interaction of charged matter with the electromagnetic field. The first formulation of this field theory used vector fields to describe the electric and magnetic fields. With the advent of special relativity, a more complete formulation using tensor fields was found. Instead of using two vector ...
Electric and magnetic fields of an electromagnetic wave along an axis. In vacuum these two fields are orthogonal and propagate at the speed of light as predicted by Maxwell. In 1864, James Clerk Maxwell published "A Dynamical Theory of the Electromagnetic Field" in which he compiled all known equations of electricity and magnetism.