Non-technical introduction to topics in electromagnetism
This article is about a conceptual understanding of the topic. For a more detailed mathematical treatment, see electromagnetism.
Electromagnetism is one of the fundamental forces of nature. Early on, electricity and magnetism were studied separately and regarded as separate phenomena. Hans Christian Ørsted discovered that the two were related – electric currents give rise to magnetism. Michael Faraday discovered the converse, that magnetism could induce electric currents, and James Clerk Maxwell put the whole thing together in a unified theory of electromagnetism. Maxwell's equations further indicated that electromagnetic waves existed, and the experiments of Heinrich Hertz confirmed this, making radio possible. Maxwell also postulated, correctly, that light was a form of electromagnetic wave, thus making all of optics a branch of electromagnetism. Radio waves differ from light only in that the wavelength of the former is much longer than the latter. Albert Einstein showed that the magnetic field arises through the relativistic motion of the electric field and thus magnetism is merely a side effect of electricity. The modern theoretical treatment of electromagnetism is as a quantum field in quantum electrodynamics.
In many situations of interest to electrical engineering, it is not necessary to apply quantum theory to get correct results. Classical physics is still an accurate approximation in most situations involving macroscopic objects. With few exceptions, quantum theory is only necessary at the atomic scale and a simpler classical treatment can be applied. Further simplifications of treatment are possible in limited situations. Electrostatics deals only with stationary electric charges so magnetic fields do not arise and are not considered. Permanent magnets can be described without reference to electricity or electromagnetism. Circuit theory deals with electrical networks where the fields are largely confined around current carrying conductors. In such circuits, even Maxwell's equations can be dispensed with and simpler formulations used. On the other hand, a quantum treatment of electromagnetism is important in chemistry. Chemical reactions and chemical bonding are the result of quantum mechanical interactions of electrons around atoms. Quantum considerations are also necessary to explain the behaviour of many electronic devices, for instance the tunnel diode.
and 24 Related for: Introduction to electromagnetism information
thing together in a unified theory of electromagnetism. Maxwell's equations further indicated that electromagnetic waves existed, and the experiments of...
physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is...
electromagnetism section of the Physics Graduate Record Examinations (Physics GRE) except circuit analysis. Griffiths, David J. (1981). Introduction to...
optics centuries before light was understood to be an electromagnetic wave. However, the theory of electromagnetism, as it is currently understood, grew out...
the radiation pressure of an electromagnetic wave is (formula)." Cloude, Shane (1995). An IntroductiontoElectromagnetic Wave Propagation and Antennas...
Relativistic electromagnetism is a physical phenomenon explained in electromagnetic field theory due to Coulomb's law and Lorentz transformations. After...
This article summarizes equations in the theory of electromagnetism. Here subscripts e and m are used to differ between electric and magnetic charges. The...
science research to study the properties of materials at high magnetic fields. Dipole magnet – the most basic form of magnet Electromagnetism Electropermanent...
given in Ashby 2003. An accessible introductionto tests of general relativity is Will 1993; a more technical, up-to-date account is Will 2006. The geometry...
generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism. Electromagnetic induction has...
application of quantum mechanics toelectromagnetism, i.e., quantum electrodynamics, gauge symmetry applies to both electromagnetic waves and electron waves....
the quantum theory of the electromagnetic force. Understanding QED begins with understanding electromagnetism. Electromagnetism can be called "electrodynamics"...
"Pulsed Eddy Current in Corrosion Detection". Hugo L. Libby, IntroductiontoElectromagnetic Nondestructive Test Methods, New York : Wiley-Interscience...
quantization of the electromagnetic field and the development of quantum electrodynamics. The empirical investigation of electromagnetism is at least as old...
important role in the modern theory of classical electromagnetism. It gives formulas for how electromagnetic objects, in particular the electric and magnetic...
Electromagnetic compatibility (EMC) is the ability of electrical equipment and systems to function acceptably in their electromagnetic environment, by...
Maxwell's equations of electromagnetism appeared to be incompatible with Newtonian mechanics, and the Michelson–Morley experiment failed to detect the Earth's...
In electromagnetism, a magnetic dipole is the limit of either a closed loop of electric current or a pair of poles as the size of the source is reduced...
also have extensive applications in physics: Electromagnetic tensor (or Faraday's tensor) in electromagnetism Finite deformation tensors for describing deformations...
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. The current density...
linked toelectromagnetism in 1845, when Michael Faraday noticed that the polarization of light traveling through a transparent material responded to a magnetic...
do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist: gravity electromagnetism weak interaction...
direction behaves as an additional force similar toelectromagnetism. These and other models of electromagnetism and gravity were pursued by Albert Einstein...
Global Information