What does Snell's Law describe?

Snell's Law specifically describes the relationship between the angles of incidence and refraction when a wave, such as light, passes from one medium into another with a different refractive index. It is mathematically represented as n1 sin(θ1) = n2 sin(θ2), where n1 and n2 are the refractive indices of the two media, and θ1 and θ2 are the angles of incidence and refraction, respectively. This law is crucial in understanding how light bends when it moves between materials like air and glass, leading to phenomena such as the distortion of images or the formation of rainbows. The accurate understanding of Snell's Law is important in fields ranging from optics to photography and even in designing optical instruments, illustrating its broad significance in practical applications.