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== Electric and Magnetic Fields ==
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An electromagnetic field is a physical field produced by electrically charged objects. The electromagnetic field can be viewed as the combination of an electric field and a magnetic field. The electric field is produced by stationary charges, while the magnetic field is produced by moving charges, i.e. electric currents. The electromagnetic field propagates indefinitely at the speed of light through a vacuum space. The oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy propagation, thus forming a propagating transverse wave. The way in which charges and currents interact with the electromagnetic field is described by Maxwell's equations.
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[[Image:EM wave1.png|thumb|left|540px| Propagation of the electric and magnetic fields associated with an electromagnetic wave.]]
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== Maxwell's Equations in Differential Form ==
:<math> \nabla . \mathbf{M} - \dfrac{\partial \rho_m}{\partial t} = 0 </math>
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[[Image:EM wave1.png|thumb|left|540px| Propagation of the electric and magnetic fields associated with an electromagnetic wave.]]
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== The Wave Equations ==