2014 · Q1
The upper and lower portions in common type of bi-focal lenses are respectively
General KnowledgePhysics
- Aconcave and convex
- Bconvex and concave
- Cboth concave of different focal lengths
- Dboth convex of different focal lengths
Explanation
In common bi-focal lenses the upper portion is concave (for distance vision) and the lower is convex (for near vision).