What does an electromagnetic wave consists of ? On what factors does its velocity in vacuum depend ?

Explanation

Maxwell concluded that the variation in electric and magnetic field vectors perpendicular to each other leads to the production of electromagnetic waves in space. They can travel in space even without any material medium. These waves are called electromagnetic waves. According to Maxwell, electromagnetic waves are those waves in which there are sinusoidal variation of electric and magnetic field vectors at right angles to each other as well as at right angles to the direction of wave propagatipn. Thus electomagnetic waves have transverse nature.
Electric field `E_(x)=E_(0)` Sin (kz-`omegat`)
Magnetic field `B_(y)=B_(0)sin(kz -omegat)`
Where K is propagation constant `(K=(2pi)/(lambda))`
The velocity of electromagnetic waves C=`(1)/(sqrt(mu_(0)epsi_(0))`
Velocity of E.M waves depends on
i) Permeability in free space `(mu_(0))`.
ii) Permittivity in free space `(epsi_(0))` .
Velocity of e.m waves is `3 xx 10^(8)` m/s.