At the end of this activity, students should be able to: û explain the principle of the formation of images by lenses. û define focal point and focal length. û calculate the image distance and the size of an image when the size of the object and its distance are given. û define the power of a lens. û determine the focal point given the shape of a lens and its refractive index. û calculate the magnification. û use the lens formula.

Originally released by Learnetic, 2016.