Computer Applications
Define the terms focus and focal length of a concave mirror. Draw diagram to illustrate your answer.
Answer
Focus of a concave mirror — The focus of a concave mirror is a point on the principal axis through which the light rays incident parallel to the principal axis, pass after reflection from the mirror.
Focal length of a concave mirror — The distance of focus F from the pole P of the mirror is called the focal length of the mirror.
i.e., focal length f = PF.
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