What does convergence measure in terms of light rays?

Convergence in optics specifically refers to the way that light rays come together at a point. When light rays diverge from a source, they can converge when focused by a lens or another optical system. The concept of convergence is crucial in understanding how lenses form images, as it determines the focal point where the light rays meet after passing through the lens.

When two light rays are described as converging, it indicates that they are changing direction and moving towards one another, ultimately intersecting at a designated point. This principle is particularly significant in areas such as vision correction, where the alignment and focus of light rays onto the retina are essential for clear vision.

Other options, such as the speed of light, intensity, or color spectrum, do not pertain directly to the concept of convergence in the context of light rays. The speed of light is a constant in a vacuum, intensity refers to the brightness or power of light, and the color spectrum describes the different wavelengths of light. Understanding these distinctions helps clarify why the focus on the direction of travel of light rays is fundamental to the concept of convergence.