Question #72152

1 Answer
Mar 25, 2017

Electromagnetic waves are non elastic waves in the sense that they don't really need a material medium for their propagation like sound waves do.

EM waves, as I shall call them are basically perpendicularly oscillating electric and magnetic fields propagating in space. The Oscillating fields oscillate transversely i.e. perpendicular to the direction of propagation.

Their velocity in a particular medium is determined thus by the electrical and magnetic properties of the medium.
In vacuum, they propagate with a velocity approximately given as
#c = 3*10^8 ms^(-1)#

In presence of material medium their velocity is smaller than this and is given as

#v = (epsilon*mu)^(-1/2)#
#ε# is the electrical permittivity and
#μ# is the magnetic permeability.