A lens that is thin in the middle and thick at the edges is called a concave lens. The most common form of a concave lens has both surfaces depressed inward in the middle. Three types of concave lenses are listed and then shown in the figure below.
3 Types of concave lens class 10
The three types of concave lenses are Double Concave, Plano-Concave, and Convexo-Concave.
Read our notes on Spherical Lens class 10
Double Concave Lens – When both the surfaces of a concave lens are concave (depressed inward) then the lens is called a Double Concave lens.
Plano-Concave Lens – When one surface of a concave lens is plane and the other surface is concave then the lens is called a Plano-concave lens.
Convexo-Concave Lens – When one surface of a concave lens is convex and the other surface is concave then the lens is called a Convexo-Concave lens.