1. Focal Point of a Converging Lens Parallel rays from a distant source of light. Are all redirected to the focal point. Focal length f (meters) A flatter lens will have a longer focal length.

2. f f Image formation with a convex lens Object (what we are trying to make a picture of) 1. Ray parallel to axis goes through f on the opposite side of the lens. 2. Ray through f on the object side of the lens emerges parallel to the axis. 3. Ray through the centre of the lens is not bent. The emerging rays intersect to form the image. Object distance d o Image distance d i

3. f f Image formation with a convex lens Object (what we are trying to make a picture of) The emerging rays intersect to form the image. Object distance d o Image distance d i Lens equation tells us where to find the image. Let’s see if it works.