Geometrical optics describes light propagation in terms of rays, which is useful in approximating the paths along which light propagates in certain classes of circumstances. Geometrical optics does not account for certain optical effects such as diffraction and interference.
Thumbnail: Parallel light rays entering a diverging lens from the right seem to come from the focal point on the right.
Paul Peter Urone (Professor Emeritus at California State University, Sacramento) and Roger Hinrichs (State University of New York, College at Oswego) with Contributing Authors: Kim Dirks (University of Auckland) and Manjula Sharma (University of Sydney). This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).