Giving birth to the refined unambiguous statement of Snell's law in ray optics

This paper reports on the ambiguity present in the long-running Snell's law of refraction of light, which is based on the traditional ambiguous definitions of the angles of incidence and refraction in ray optics. To get rid of the said ambiguity, the refined unambiguous definitions of angles of incidence and refraction reported earlier by the author have been employed to give birth to the refined unambiguous statement of Snell's law of refraction. The most interesting physical insights that resulted from the refined unambiguous statement of Snell's law are: (i) in case of refraction of light of a particular colour while passing from one optical medium to another, the ratio of the sine of the angle of incidence and the sine of the angle of refraction is approximately equal to the refractive index of the second optical medium with respect to the first optical medium and (ii) the refractive index of an optical medium 'b' with respect to another optical medium 'a' is approximately equal to the reciprocal of the refractive index of the optical medium 'a' with respect to the optical medium 'b', and vice versa. These results are entirely novel and different from those existing in the traditional literature of ray optics.