Question

What is the principal axis of lens

Answer 1

a line passing through optic centre and all foci(plural form of focus)

Answer 2

The straight line passing through the geometrical Centre of a lens and joining the two centres of curvature of its surfaces

Explanation:

• The point where a beam parallel to the foremost hub appears to diverge focalizes from a point on the vital axis after passing through the focal point. In some cases the optical axis of a focal point is called its principal axis.
• The way of a light beam along this pivot is opposite to the surfaces and, as such, will be unaltered.