«Geometrical optics, or ray optics, is a model of optics that describes light propagation in terms of rays. The ray in geometrical optics is an abstraction useful for approximating the paths along which light propagates under certain circumstances.
The simplifying assumptions of geometrical optics include that light rays:
- propagate in straight-line paths as they travel in a homogeneous medium
- bend, and in particular circumstances may split in two, at the interface between two dissimilar media
- follow curved paths in a medium in which the refractive index changes
- may be absorbed or reflected.
Geometrical optics does not account for certain optical effects such as diffraction and interference. This simplification is useful in practice; it is an excellent approximation when the wavelength is small compared to the size of structures with which the light interacts. The techniques are particularly useful in describing geometrical aspects of imaging, including optical aberrations.» – Wikipedia.




REF:
[1] Dieter Meschede, “Optics, Light and Lasers-the practical approach to modern aspects of photonic and laser physics” (Wiley-VCH, Wiinheim, 2004)
ONLINE SIMULATORS TO GET PHYSICAL INTUITION:
(1) https://phet.colorado.edu/en/simulations/geometric-optics
(2) https://ophysics.com/l.html
(3) Using MatLab: https://www.mathworks.com/matlabcentral/fileexchange/52171-lenslab
NB-“Phythematics” is meant to be a short calligraphic text containing calculus or content related to science, aiming to maximize understanding of physics and natural processes and helping science benefit society. For the fun of it. Remember, for better learning:
- Write notes in books
- Add unique visual notes to digital documents
- Stick with paper and pen for creative pursuits.

