Image Formation by Convex Lens

Image formation by convex lenses is different to image formation by concave lenses. Image properties depend on the position of the object to the lens. We can form an image with two or three light rays. The ray that passes through the focal point on the way to the lens will refract and travel parallel to the principal axis. Use a straightedge to accurately draw its path. The ray that travelled parallel to the principal axis on the way to the lens will refract and travel through the focal point. And the ray that travelled to the exact centre of the lens will continue in the same direction. Place arrowheads upon the rays to indicate their direction of travel. Extend the rays past their point of intersection. We illustrate that when the object is located at a different position, the image will be also located at a different position with its different change in the size and the direction to the optical axis.