Incident ray, coming from one medium to the boundary of another medium, is refracted with a rule derived from a physicist Willebrord Snellius. The Law of Refraction. The laws of refraction govern the behaviour of light as they pass through the interface between two media. The Laws of Refraction Incident ray, reflected ray, refracted ray and the normal of the system lie in the same plane. Laws of refraction. This law is more complicated than that for reflection, but an understanding of refraction will be necessary for our future discussion of lenses and their applications. Law of refraction definition, the principle that for a ray, radar pulse, or the like, that is incident on the interface of two media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocity of the ray in the first medium to the velocity in the second medium and the incident ray, refracted ray, and normal to the surface at the point of incidence all lie in the same … the angle of reflection, r, is the angle between the normal and reflected ray. The law of refraction gives us a way of predicting the amount of bend. From the above-depicted activity, we can say that refraction of light follows two laws: It is generally known as Snell’s Law. When light travels from one medium to another, it generally bends, or refracts. The law of refraction is also known as Snell's Law, named for Willobrord Snell, …