" Spherical aberration in a lens "

Spherical aberration in a thin lens can be reduced by

Spherical aberration in a thin lens can be reduced by

What is the cause of spherical aberration in lenses? State a method to minimise the defect.

Draw a diagram to illustrate spherical aberration in a convex lens.

To minimize spherical aberration two lenses of focal lengths f_(1) and f_(2) are placed with a distance of separation equal to