Which RF behavior is defined as the bending of a wave as it passes through a medium of different density?

• A. Diffraction.
• B. Refraction.
• C. Reflection.
• D. Absorption.

Answer: (B)

Refraction is the bending of a wave as it passes from one medium into another with a different propagation speed due to the medium’s density or dielectric properties. In radio frequency waves, the speed depends on the medium’s dielectric constant, so when the wave crosses the boundary, its velocity changes and the wavefront changes direction. The frequency stays the same at the boundary, but the wavelength adjusts to the new speed, which is why the path appears to bend.

Snell’s law ties the incident and refracted directions to the speeds (or refractive indices) of the two media, explaining why the bend is toward the normal when entering a denser medium (slower speed) and away from the normal when entering a less dense medium (faster speed). This behavior is distinct from diffraction (bending around edges), reflection (bouncing back), and absorption (energy loss).