रे वृत्तिकी

Study Notes

Ray optics, also called geometrical optics, is a branch of physics that describes light propagation in terms of "rays" . It is concerned with the behavioural pattern and properties of visible light, infrared light, and ultraviolet light . Ray optics is used to study how images form in an optical system, and it has applications in medical diagnosis, therapeutic and surgeries of human tissues, and optical microscopy .

The crux of ray optics lies in Fermat's principle of light propagation through air and other mediums . The postulates of ray optics are:

Light traveling through a medium is characterized by its refractive index, n ≥ 1.
The refractive index of a medium is n = c0/c, where c0 and c are the speed of light in a vacuum and medium,
The speed of light in a vacuum is c0 = 299,792,458 (1/s) .

Ray optics is used to describe the behaviour of light in terms of rays, which are the geometric approximation of light propagation . This approximation is valid for light with a small-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among-among