How is a reflected ray defined in optics?

A reflected ray is defined as the light ray that bounces off a reflective surface. This occurs due to the principles of reflection, where light rays strike a surface and are redirected according to the law of reflection. The law states that the angle of incidence, the angle at which the incoming ray strikes the surface, is equal to the angle of reflection, which is the angle at which the ray is reflected away from the surface.

This definition is distinct from other types of rays mentioned in the options. For instance, rays emitted from a source pertain to emitted light rather than reflected light. Rays passing through a lens involve refraction, not reflection, and while light does generally travel in straight lines, this characteristic is not exclusive to reflected rays. Thus, the role of a reflected ray is specifically tied to its interaction with reflective surfaces, making the correct definition the one that describes this bouncing action.