State difference between a convex and a concave lens in their (a) appearance, and (b) action on the incident light.
Convex lens:
(a) These typesof lenses are thickerin themiddle in comparison totheiredges.
(b) They converge the rays parallel to the principal axis.
Concave lens:
(a) These typesof lenses are thickerin theedges in comparison totheir middle.
(b) They diverge the rays parallel to the principal axis.