Electromagnetic waves in air are transverse. These waves consist of oscillating electric and magnetic fields that are oriented perpendicular to the direction of wave propagation. This is in contrast to longitudinal waves, such as sound waves in air, where the oscillations occur in the same direction as the wave travels. The ability of electromagnetic waves to be polarized is a direct result of their transverse nature, as the electric and magnetic fields can oscillate in different planes relative to the direction of propagation. read more >>

Longitudinal waves such as sound cannot be polarized. Light and other electromagnetic waves are transverse waves made up of mutually perpendicular, fluctuating electric and magnetic fields. ... An unpolarized electromagnetic wave traveling in the x-direction is a superposition of many waves.read more >>