What occurs when light hits a plane surface?

When light hits a plane surface, it undergoes a change in its direction of travel due to the phenomenon known as reflection. This is a fundamental principle in physics, where light waves bounce off surfaces. In the case of a plane (flat) surface, the angle at which the light hits the surface—called the angle of incidence—will equal the angle at which it reflects off the surface—known as the angle of reflection. This relationship is described by the law of reflection and is why mirrors work effectively.

Reflection is particularly important in various applications, such as optical devices, everyday mirrors, and the behavior of light in different materials. The characteristics of the surface also play a role; a smooth, shiny surface will reflect light more effectively and clearly compared to a rough surface.

In contrast to this, options discussing absorption, unchanging light paths, or light returning to the source do not accurately describe the behavior of light upon striking a plane surface under typical circumstances. While absorption may occur with certain materials, that is not a characteristic of reflection specific to plane surfaces. Similarly, while it is possible for light to travel without change in a vacuous space, when it interacts with a surface, a directional change is the primary outcome.