1. Convex Lens A convex lens curves outward; it has a thick center and thinner edges

2. Principle Focus When a beam of light parallel to the principle axis passes trough a converging lens it is refracted so as to converge to a point on the Principle Focus

3. Convex lens F FC Principle Axis C = Optical Centre CF = FC = Focal Length F = Principle Focus

4. Kinds of converging lenses 1.Biconvex 3. Convex concave 2. Plano convex

5. Ray construction diagrams for converging lens 1. A ray parallel to the principle axis which is refracted through the principle focus F 2. A ray through the principle focus F which is refracted parallel to the principle axis. 3. A ray through the optical center C which is undeviated for a thin lens

6. 1. A ray parallel to the principle axis which is refracted through the principle focus F F F C

7. 2. A ray through the principle focus F which is refracted parallel to the principle axis F F C

8. 3. A ray through the optical center C which is undeviated for a thin lens 3. A ray through the optical center C which is undeviated for a thin lens F F C

9. Images Formed by a convex lens Images Formed by a convex lens Object between 2F and F Images : real, inverted, larger FF C 2F

10. Magnification Which m = magnification image s’ = distance of image from lens s = distance of object from lens h’ = height of image h = height of object Note : F (positive)

11. Example 1. The convex lenses has a focal length of 4 cm. An object 6 cm from the lens, If the height of an object 2 cm. Calculate magnification of image ?