What is the optical axis?

1 Answer
A08
Feb 26, 2017

Optical axis of a lens is an imaginary straight line which passes through the geometrical center of a lens joining the two centers of curvature of surfaces of lens. It is also called principal axis of the lens.

met.reading.ac.uk

As shown in the figure above, #R_1 and R_2# are centers of curvature of of two surfaces. Straight line joining these two is the optical axis.

A ray of light traveling along this axis is perpendicular to the surfaces and, therefore, its path remains un-deviated.

The optical axis of a curved mirror is the line passing through its geometric center and center of curvature.

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