When a wave reflects off an irregular surface, it radiates in more than one direction. This form of reflection is called ______.

• A. Specular
• B. Backscatter
• C. Diffuse
• D. Scattering

Answer: (C)

Diffuse reflection is the idea being tested. When a wave meets a rough, irregular surface, each tiny facet is oriented differently, so the reflected waves leave in many different directions rather than in a single, mirror-like direction. That spread of reflected energy is what we call diffuse reflection.

The other terms aren’t as precise here. Specular reflection describes smooth surfaces that reflect light in one direction, like a mirror. Backscatter refers to energy returning toward the source, not necessarily spreading in many directions. Scattering is a broader term for how waves spread in many directions in various media, but for a surface interaction described as reflection off a rough surface, diffuse reflection is the specific and correct description.