SNELL

Snell is a surname of Dutch origin. In scholarship and science, it is most commonly encountered in reference to Snell's law of refraction in optics. The law is named after Willebrord Snell (also listed as Snellius), a Dutch mathematician and astronomer who formulated it in the early 17th century.

Snell's law describes how light bends when crossing the boundary between two media with different refractive indices. If a light ray passes from a medium with refractive index n1 into a second medium with index n2, and θ1 and θ2 are the angles of incidence and refraction measured from the normal, then n1 sin θ1 = n2 sin θ2. Equivalently, sin θ1 / sin θ2 = n2 / n1. The law provides the foundation for understanding and designing optical devices such as lenses, prisms, and optical fibers, and it is essential for predicting the paths of light in complex systems.

Beyond the law, the Snell surname appears in the historical record of Dutch mathematics and astronomy, attached to several scholars across generations. In modern usage, Snell's law remains a standard term in physics and engineering, reflecting the enduring influence of Willebrord Snell's work on the science of light.