The laws of refraction, also known as Snell's Law, describe how light bends when it passes from one medium to another. 1. The incident ray, the refracted ray, and the normal to the surface at the point of incidence all lie in the same plane. 2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant for any given pair of media. This constant is equal to the ratio of the speed of light in the second medium to the speed of light in the first medium, or equivalently, the ratio of the refractive index of the second medium to the refractive index of the first medium. Mathematically, Snell's Law is expressed as: n₁ sin(θ₁) = n₂ sin(θ₂) Where: n₁ is the refractive index of the first medium. θ₁ is the angle of incidence. n₂ is the refractive index of the second medium. θ₂ is the angle of refraction.