Question

$\huge\bf\underline{\underline{Question}}$

what is principal exis ? ​

Answer 1

Answer:

$\huge{\underline{\color{teal}{\textsf{\textbf{~~~Answer}}}}}$

The principal axis is called a line that passes via the centre of the surface of a spherical mirror or lens and through the centre of curvature of all segments of the mirror or lens.

Answer 2

$\sf\underline{Principal~axis:}$

The line joining center of curvatures and the pole or the line joining center of two curved surfaces is called principal axis.

Have a good day!