Thin lenses

Core concepts and learning points for this section:

Syllabus Points

3.2.3.1 Describe the action of thin converging and thin diverging lenses on a parallel beam of light
3.2.3.2 Define and use the terms focal length, principal axis and principal focus (focal point)
3.2.3.3 Draw and use ray diagrams for the formation of a real image by a converging lens
3.2.3.4 Describe the characteristics of an image using the terms enlarged/same size/diminished, upright/inverted and real/virtual
3.2.3.5 Know that a virtual image is formed when diverging rays are extrapolated backwards and does not form a visible projection on a screen

3.2.3.6 Draw and use ray diagrams for the formation of a virtual image by a converging lens
3.2.3.7 Describe the use of a single lens as a magnifying glass
3.2.3.8 Describe the use of converging and diverging lenses to correct long-sightedness and short- sightedness