Difference between revisions of Focal length
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(Created page with "The focal length of a lens is the distance from the lens to the point at which parallel incident light converges. For example, since the rays from the sun are effectively para...") |
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Revision as of 09:06, 2 June 2020
The focal length of a lens is the distance from the lens to the point at which parallel incident light converges. For example, since the rays from the sun are effectively parallel, a magnifying glass can be used to produce an intense spot at a distance equal to the focal length.
For a diverging (concave) lens, the focus is virtual : it is the distance behind the lens from which incident parallel light appears to emanate.