Answer to Question #64279 in Mechanics | Relativity for Abdul Rahman

Question

There is no mass, no charge in space or vacuum then how electric and magnetic fields are varying in space?

Answer 1

The propagation of electromagnetic waves either in a certain medium or in vacuum is due the mutual changes between the electric and magnetic field. Referring to the four Maxwell’s equations and from the wave equations of the electric and magnetic fields, anyone can conclude that the spatial variation of the electric field is always accompanied with a time varying of the magnetic field and that the spatial variation of the magnetic field is always accompanied with a time varying of the electric field. These variations in electric and magnetic fields lead to the transfer of the energy which is carried by the EM wave. Therefore, EM waves will constantly propagate with non-stopping until meet an obstacle or barrier.