The lens with a curved shape is known as convex lens.A convex lens causes rays to converge on a single point,the focal point. This will form a visual image of the object.The image may be real.
This type of lens is often used for close examination of small objects, such as rare stamps or coins.The rays are parallel as they approach the lens. As each ray reaches the glass surface, it refracts according to the effective angle of incidence at that point of the lens.
A convex lens is a lens which both sides of the lens are curved out like outside of a sphere. When nearby objects are viewed through a convex lens they appear larger. Therefore a convex lens by it self may be used for magnification of objects. With a plain convex lens it is possible to achieve magnification of the order of 5. Because a convex lens is used for magnifying objects it is commonly also called a magnifying glass. A convex lens used for magnifying often comes protected by a rim which has a small handle extending from it for holding the glass at appropriate distance from the object to be viewed.
A convex lens is the most commonly seen lens. A convex lens is round shaped and is usually made out of clear class or plastic. It is concave in shape and is often used with a Concave Lens. It is used to make things larger by bending lights rays so that they move together. They are called three types of lenses positive lenses, plus lenses ,and converging lenses.
“Concavo-convex lenses have another name—positive meniscus.”
Convex lenses are used to treat people who are nearsighted. Their glasses often have a convex lens. They have one convex surface and one concave surface. Between the two, the glasses can bend the light just the right amount before it gets to your eyes.
A fracting telescope uses two such lenses to allow magnification of images.