The bending of electromagnetic waves caused by a change in the density of the medium through which the waves are passing is referred to as what?

• A. Polarization
• B. Multipathing
• C. Inversion
• D. Refraction

Answer: (D)

Refraction is the bending of electromagnetic waves when they pass into a medium with a different density (and thus a different refractive index). When the wave enters the new medium, its speed changes, and to satisfy Snell's law the ray changes direction. This is the classic bending effect you observe as waves cross boundaries between materials with different densities, such as air layers in the atmosphere that vary in temperature and humidity. Polarization is about the orientation of the electric field, not bending. Multipathing involves the signal taking multiple routes due to reflections and other interactions, not a single bend at a boundary. Inversion refers to a different atmospheric condition and isn’t the cause of the bending described here.