GSC International 75mm Diameter Double-Convex Lens - 20cm Focal Length

in this video we're going to go over the fins lens equations we're going to use it to solve certain problems and we're going to draw a few ray diagrams so there's two lens that you need to be familiar with this is called the convex lens also known as the converging lens notice that it's thicker at the center the next one is the concave lens this is also known as the divergent lens which is thinner at the center something important that you need to keep in mind is the focal length for converging lens the focal length is positive and for a diverging lens the focal length is negative so let's draw a convex lenss the horizontal line is known as the principal axis the focal length is the distance between the point F and the center of the lens so that's the focal length it's also the same distance on the other side so it appears on both sides the focal length is half of the radius of curvatur