What type of reflection occurs when parallel rays hit a rough surface?

When parallel rays of light strike a rough surface, the type of reflection that occurs is diffused reflection. This phenomenon happens because the roughness of the surface causes the incoming parallel rays to scatter in multiple directions rather than reflecting uniformly. Each tiny uneven surface element acts like a mirror that reflects light at various angles, leading to a diffuse effect. As a result, the light is spread out rather than directed in a single beam, allowing visibility from multiple angles and making the surface appear illuminated uniformly.

In contrast, specular reflection occurs on smooth surfaces where light rays reflect at the same angle they arrive, creating clear and distinct images. Regular reflection is essentially a synonym for specular reflection, emphasizing that the reflecting surface is uniform. Scattered reflection, while similar to diffused reflection, is less commonly used in this context and does not specifically refer to the uniform scattering of parallel rays by rough surfaces. Thus, the correct identification of diffused reflection highlights the nature of how light interacts with irregular surfaces.