Question

What are electromagnetic waves?

Answer 1

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.

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 = (epsilonmu)^(-1/2)` where `epsilon` is the electrical permittivity and `mu` is the magnetic permeability.