Final answer:
The term for the distance from the center of a sphere to a point on its surface is the radius. This concept is important in both geometry and the study of optics, where it relates to determining the properties of images formed by lenses.
Step-by-step explanation:
The distance from the center of a sphere to a point on the sphere is known as the radius. This concept is fundamental in understanding geometric properties of spheres.
In the context of optics and lenses, such as in Figures 25.30, 25.31, and 25.32 mentioned in the reference, the term object distance (do) and image distance (di) are used to describe the distances of objects and their corresponding images from the center of a lens. Whereas, the terms radius of curvature refer to the radius of the spherical surfaces that constitute parts of the lens.
These concepts are integral to the study of geometry and optics, where they are used to determine the size and position of images created by lenses using ray tracing methods and equations such as the thin lens equation.