### Derivation of the Wave Speed

The first equation is the partial differential equation for the electric field
that resulted from Maxwell's equations.
The second equation above is the general form of the wave equation, where *v* is
called the phase speed of the wave. Comparing the two equations and evaluating the
phase speed for the electromagnetic wave:

"http://www.physics.udel.edu/~watson/phys208/wave-eqn4.html"

Last updated Dec. 9, 1997.

Copyright George Watson, Univ. of Delaware, 1997.