EM Wave Propagation – Field orientations in homogeneous, isotropic media As an electromagnetic wave propagates through a homogeneous, isotropic, lossless medium, which statement is correct?

Introduction / Context:
In free space or any homogeneous, isotropic, lossless medium, plane electromagnetic waves are transverse. This geometric relationship underlies polarization, antenna patterns, and radiative transfer models used in remote sensing.

Given Data / Assumptions:

• Medium: homogeneous, isotropic, and lossless.
• Plane-wave approximation.

Concept / Approach:
For a plane wave, the electric field E, magnetic field H, and the direction of propagation k form a mutually orthogonal triad. Hence E ⟂ H, and both are ⟂ to k (the Poynting vector S is along k).

Step-by-Step Solution:
Identify plane-wave property: transversality.E ⟂ H ⇒ option (a) true.E ⟂ k and H ⟂ k ⇒ option (b) true.Therefore combined statement (c) is correct.

Verification / Alternative check:
Maxwell’s equations in homogeneous media lead to wave equations with ∇·E = 0 and ∇·H = 0 for plane waves, enforcing transversality.

Why Other Options Are Wrong:

• (d) contradicts wave transversality.
• (e) applies to longitudinal waves, not EM plane waves in such media.

Common Pitfalls:
Assuming longitudinal components exist in free space; they appear only in waveguides/plasmas under special conditions.

Final Answer:
Both (a) and (b)