Diffraction wraps around obstruction.

• A. SERRATED RANGE RINGS
• B. Water in the Waveguide
• C. Diffraction
• D. Sub Refraction

Answer: (C)

Diffraction is the bending of waves around obstacles and through openings. When radar energy meets an obstruction, the portions of the wavefront that reach the edges act like new sources, sending energy into the region behind the object. This lets the signal wrap around the edge and reach areas that aren’t in a direct line of sight, which is why you can still detect reflections from targets even when they’re not in a clear path. In radar terms, diffraction explains why energy appears in the shadow zone and can affect the strength and pattern of returns. The other options don’t describe this behavior: serrated range rings aren’t a basic wave phenomenon, water in a waveguide is an equipment issue, and sub refraction deals with atmospheric bending of the beam rather than how waves wrap around physical obstructions.