There are 2 main types of lenses :

How to draw ray diagrams

We represent the object by an arrow  () and 2 construction rays are drawn from the top of the object.

Link to Ray Diagram page

The position and size of an image produced by a convex lens, can be found by scale drawing using graph paper; or by using the lens formula.

where

When f  is measured in metres, represents the power of the lens in dioptres.

For further information go to: Defects of Vision and their Correction

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