In most cases light can be described as an electromagnetic wave. Geometrical optics is an approximation in which the waves can be represented as straight-line rays. This approximation is valid if the light waves do not meet obstacles comparable in size to the wavelength of radiation.
Generalic, Eni. "Geometrical optics." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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