Question

We know that wave is a disturbance in medium without the displacement of the particles then why light or any other electromagnetic 'waves' are actually waves as they can also travel without medium and displacing the particles??

Answer 1

It is a mechanical wave (periodic or non-periodic) which can be viewed as a disturbance in a medium through which it travels. The particles of the medium oscillate about their mean position and the average displacement of the particles is not affected. Electromagnetic waves are type of transverse wave which does not require any material medium for there propagation. In this electric field vector and magnetic field vector both oscillates in a direction perpendicular to the propagation of the wave.