1. Waves Drawing ray diagrams for converging lenses

2. Aim To find the location of an image produced by a converging lens, without having to carry out practical work To determine the properties of an image (size etc.)

3. Types of lens Lenses are classified by their effect on parallel light rays Lenses either cause the rays to spread apart (diverging) of come together (converging)

4. Drawing ray diagrams There are 3 standard light rays that you can use to find the location of an image. For a ray diagram to give the correct answer it must be drawn carefully so use a ruler and a sharp pencil.

5. Draw principal axis & lens (remember arrow heads on lens) Mark on both focal points Draw object arrow and label O Draw first construction ray (from very tip of arrow) and direction arrows F F O

6. On the same diagram draw the 2 nd construction ray from same point as the first

7. On the same diagram draw the 3 rd construction ray from same point as the first two

8. The Image If you’ve done this carefully, all three rays should cross in one place. This is where the image is formed. Draw the image arrow from where the light rays cross to the principal axis. Label this arrow I. Describe the image: real/virtual; inverted/upright; enlarged/diminished; closer to the lens/same distance/further away; magnification Magnification = height of image/height of object Magnification has no unit

9. Summary

10. Example Light rays cross on other side of lens so image is REAL Image is INVERTED Image is CLOSER TO LENS than object Image is DIMINISHED