The most significant contribution of Willebrord Snellius (Willebrord Snell) to science is the formulation of the Law of Refraction, also known as Snell's Law. This fundamental principle governs how light (or other waves) bends when it passes from one medium to another.
Relationship: It establishes a precise mathematical relationship between the angles of incidence and refraction, and the refractive indices of the two media.
Refractive Index: The refractive index (n) of a medium is a measure of how much light slows down and bends within that medium compared to a vacuum. A higher refractive index means light bends more.