An electromagnetic wave propagates along the +x direction in a dielectric medium having a relative permittivity _r = 4 and relative permeability _r = 1 . At a particular point in space and time, the electric field vector is E = -12 j V m ⁻¹ . What is the corresponding magnetic field vector B at that point?

Step-by-step solution

First, find the speed of the electromagnetic wave in the given dielectric medium. The speed v is given by: v = c _r _r v = 3 10^8 4 1 = 3 10^8 2 = 1.5 10^8 m s ⁻¹ The magnitude of the magnetic field B is related to the magnitude of the electric field E by the speed of the wave in the medium: B = E v B = 12 1.5 10^8 = 8 10⁻⁸ T The direction of wave propagation c is given by the cross product of the directions of the electric and magnetic fields: c = E B Given that the wave propagates along the +x direction, c = i .