1. Lenses

10. Concave Lens Ray Diagrams Ray 1 - travels from the tip of the object parallel to the principal axis . When it emerges from the lens, it appears to come from the principal focus ( F )

11. Concave Lens Ray Diagrams Ray 2 - travels from the tip of the object through the optical centre of the lens and is not refracted .

12. Concave Lens Ray Diagrams The image occurs where these rays appear to intersect .

15. Convex Lenses

16. Convex Lens Ray Diagrams Ray 1 - travels from the tip of the object parallel to the principal axis . When it emerges from the lens, it travels towards the principal focus (F)

17. Convex Lens Ray Diagrams Ray 2 - travels from the tip of the object through the optical centre of the lens and is not refracted .

18. Convex Lens Ray Diagrams The image occurs where these rays appear to intersect .

20. Case 1: Real Reduced Inverted Attitude Size Type

21. Case 2: Real Enlarged Inverted Attitude Size Type

22. Case 3: No Image Formed! Attitude Size Type

23. Case 4: Virtual Enlarged Upright Attitude Size Type