explain with calculations. length of optical path in refraction?

Brittanie Zakutney: Optical Length

Myron Leftwich: "In optics, optical path length (OPL) or optical distance is the product of the geometric length of the path light follows through the system, and the index of refraction of the medium through which it propagates. " (see reference below).Your question does not tell us the geometric length of the path light follows through the system, only the thickness of the media. These are only the same thing if the light passes directly through the medium, rather than obliquely through it. This would correspond to normal incidence if the media were in the form of parallel-sided plates. For any other type of path we would need more information before an answer could be given.If we take d1 and d2 to be the lengths of the light-paths through the media, we can calculate optical path length as M1*d1 + M2*d2 which is answer (B)...Show more