Light is an electromagnetic wave. To explain this, we consider the Maxwell's equations, the four equations the describe all of electricity and magnetism. The first equation is Ampere's law, only that the second term on the right-hand-side is new. The second equation is Lenz's law. The third equation is Gauss's law and expresses the fact that electric field lines begin and end only at charges. The fourth equation is the magnetic equivalent of Gauss's law, expressing tha fact that magnetic field lines never begin or end. After a bit
of non-trivial differential calculus one can show that
both the electric and magnetic field obey wave equations.
The speed c^{2}
=1/(e_{0}m_{0})
= 2.998 m/s. The details
of an electromagnetic wave are fairly complicated. If the
wave moves in -axis. The magnetic field
also oscillates and is perpendicular to both the magnetic
and electric fields. If the electric field is oscillating
in the z-direction, we say the
wave is xpolarized along the -axis.
The figure below illustrates the behavior of an
electromagnetic wave which is polarized along the x-axis.xThe forms of the electric and magnetic field in the wave are: where the frequency
and wavelength are related by f..l |