Thin lenses

1 Describe the action of thin converging and thin diverging lenses on a parallel beam of light

2 Define and use the terms focal length, principal axis and principal focus (focal point)

3 Draw and use ray diagrams for the formation of a real image by a converging lens

4 Describe the characteristics of an image using the terms enlarged/same size/diminished, upright/inverted and real/virtual

5 Know that a virtual image is formed when diverging rays are extrapolated backwards and does not form a visible projection on a screen

6 Draw and use ray diagrams for the formation of a virtual image by a converging lens

7 Describe the use of a single lens as a magnifying glass

8 Describe the use of converging and diverging lenses to correct long-sightedness and short-sightedness