Question

Define the term ‘Principal axis for spherical mirrors’ .

Answer 1

1. The principal axis is the straight line running through point ‘C’ which is the center of curvature and the point ‘P’ which is the pole of the spherical mirror.
2. The following diagram shows the principal axis of the curved mirrors

In the given diagram the dotted line passing through the reflecting surface at pole ‘P’ and the center of curvature ‘C’ is described as the principal axis.