Question

Question #81661

Answer 1

The words concave and convex refer to the shape of the lens itself.

Explanation:

Very simply, the words concave and convex refer to the shape of the lens itself.

con·cave
/känˈkāv,ˈkänˌkāv/
adjective
`" "`having an outline or surface that curves inward like the
`" "`interior of a circle or sphere.

con·vex
/känˈveks,ˈkänveks/
adjective
`" "`having an outline or surface curved outward like the
`" "`exterior of a circle or sphere.

A concave lens, therefore, has a surface that curves inward. it can do so on one or both faces of the lens and the symbol for this type of lens is a line with inward pointing arrows on it:

These lenses cause parallel rays entering the lens to diverge when they exit. This causes the image to be smaller for the viewer looking through the lens.

A convex lens has a surface that curves outward. it can do so on one or both faces of the lens and the symbol for this type of lens is a line with outward pointing arrows on it:

These lenses cause parallel rays entering the lens to converge when they exit. This causes the image to be larger for the viewer looking through the lens - this is what we normally think of as magnification.