Electromagnetic wave as the transverse wave :
It is well known fact that the electromagnetic radiation behaves as the transverse wave.
Thus the light behaves as transverse waves. This means that the electric and magnetic field disturbances are in the plane transverse to the direction of propagation of the wave. Electric and magnetic fields are also perpendicular to each other and are interrelated also.
Essential parameters of Electromagnetic wave:
For complete mathematical representation of the electromagnetic wave it is sufficient to know the following:
(a) Frequency of the wave 
or angular frequency 
: A fundamental property of the wave, so long it is propagating through a linear medium.
(b) Amplitude and the direction of electric field E0 :
(c) Propagation vector k whose magnitude is 
(c being the velocity of propagation of the em wave and its direction represents the direction of propagation of the em wave).