Final answer:
For an electromagnetic wave in a lossless medium, the value of φη, the phase angle of the intrinsic impedance, is zero, indicating no phase shift between the electric and magnetic fields. In a lossy medium, φη is nonzero and represents the energy dissipation due to the phase shift caused by the medium's conductivity. Electric permittivity and magnetic permeability are central in defining electromagnetic wave properties and behaviors.
Step-by-step explanation:
The impedance of a medium in the context of electromagnetic waves is referred to as the intrinsic impedance, symbolized as ηc. The phasor form of this complex impedance is given by ηc = |ηc|ejφη, where ζη represents the phase angle. In a lossless medium, the electromagnetic wave does not dissipate energy as it propagates. Consequently, its intrinsic impedance is purely real, meaning there is no phase difference between the electric and magnetic fields. Therefore, the value of φη for a lossless medium is zero.
In a lossy medium, where the electromagnetic wave attenuates due to energy dissipation, the intrinsic impedance has both real and imaginary components. The phase angle φη in this case represents the phase shift between the electric and magnetic fields due to the presence of conductivity in the medium. This phase shift causes the impedance to be complex and thus is directly related to the energy loss in the medium.
The electric permittivity and magnetic permeability of free space are fundamental constants that relate to Maxwell's equations, defining the speed of light in vacuum and electromagnetic wave propagation. They are also used to express the average intensity and field strengths of electromagnetic waves in different media.