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This article presents an alternative method for ray tracing to locate image position for thin lenses and
spherical mirrors without using the principle rays but arbitrary rays instead. This method can be used to engage
in fundamental geometric optics classroom to enhance students’ understanding as well as to overcome some
misconception about image formation by thin lenses or spherical mirrors particularly in cases of a partial covered lens/mirror and a compound system of lenses or mirrors dealing with virtual object.
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