Question

define principal axis of lenses​

Answer 1

Explanation:

a line passing through the center of the surface of a lens or spherical mirror and through the centers of curvature of all segments of the lens or mirror.

Optical axis, the straight line passing through the geometrical centre of a lens and joining the two centres of curvature of its surfaces. Sometimes the optical axis of a lens is called its principal axis. The path of a light ray along this axis is perpendicular to the surfaces and, as such, will be unchanged.

Answer 2

Answer:

here is your answer

An imaginary line that passes through the optical center and the center of curvature of both faces of the lens, and is perpendicular to the faces is known as the principal axis.