Question

Define the principal focus of a concave mirror.

Answer 1

The principle focus of a concave mirror is a point on its principle axis to which all the light rays which are parallel and close to the axis, converge after reflection from the concave mirror.

Answer 2

The principal focus of a concave mirror is defined as a point on the principal axis where all the light rays parallel to the principal axis meet after getting reflected from the mirror.

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