What is the outcome on light reflection when the surface is smooth?

Specular reflection occurs when light reflects off a smooth surface. This type of reflection is characterized by the light rays being reflected in an ordered and consistent manner, which allows for clear images to be reflected. Smooth surfaces, like a calm body of water or a polished mirror, provide a uniform surface that directs light rays at the same angle at which they hit the surface. As a result, the angle of incidence (the angle at which the incoming light strikes the surface) equals the angle of reflection (the angle at which light reflects away). This principle is critical in optics and is the reason why mirrors work effectively to create clear reflections.

In contrast, diffuse reflection happens on rough surfaces where light rays hit the surface at varying angles and scatter in multiple directions, resulting in a blurred or non-image-producing reflection. Light absorption would occur if the surface had a property that converts light energy into other forms of energy, effectively preventing any light from being reflected. Lastly, if the light scatters completely, it would indicate a highly irregular surface which disrupts the smoothness necessary for specular reflection. Thus, the nature of the surface determines the type of reflection: smooth surfaces lead to specular reflection, while rough or irregular surfaces lead to diffuse reflection or scattering.