Question

Diagram of bifocal lenses.

Answer 1

Bifocal lens:

1. A lens with two focus points, typically one for viewing far-off things and the other for viewing close objects, is referred to as bifocal. A bifocal is also known as a multi-focal lens.
2. Bifocals have both a concave and convex surface that is part of their refractive design.
3. When the eyeglasses are placed upright, you will notice that the concave lens is placed in the upper portion while the convex lens is placed in the lower portion of the collective lens.
4. The diagram of the bifocal lens is as follows,
   

The ray diagram of the bifocal lens is as follows: