That is why the concave lenses are called diverging lenses (2). Concave lenses are also used in the camera for better image quality. Read about our approach to external linking. Concave lenses are the most useful for binoculars. Thus, the concave lens is also known as a diverging lens while the convex lens is known as a converging lens. A lens can be convex or concave. types of concave lenses: (a) double concave or biconcave lens: both the surfaces are concave. The light converges at one point on the convex lens and then it spreads again (1) & (4). Some of the differences between convex and concave lenses are discussed below. In a ray diagram, a concave lens is drawn as a vertical line with inward facing arrows to indicate the shape of the lens. A convex lens is thought to be made up of a number of small cut prisms placed one on top of the other. After light passes through a convex lens, it is reflected and the reflected rays meet at a certain point. it is simply called a concave lens. A lens that is concave on both sides is called a double concave lens. This causes the refracted rays to turn into diverging rays. These two lenses are also differentiated on the basis of shape possessed by them. A lens is a homogeneous optical device having a transparent medium through which light is refracted they are used to converge and divert light. The position of the focal length in a convex lens is towards the front of the lens. are concave lenses. When parallel rays are incident on the concave surface of this lens, the rays are scattered. Concave and Convex Lenses - The type of lenses which converge the light beam coming from the source to one point on the other side to form an image is called as a convex lens, while the concave lens which is thinner at the centre and gets thicker as we move towards the edges is called as Concave lens. The middle of the concave lens is narrow and the edges are flattened. A convex lens is used in a magnifying glass. The curvature radius of the concave surface of this lens is less than the radius of curvature of the convex surface. Convex lens forms a real image, but it can also create a virtual image when the object is in the middle and optical center. can be removed with the help of convex lenses. Lenses are used in cameras, telescopes, binoculars, microscopes and corrective glasses. 0. The rays are incident on the convex surface of the convex lens. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.. They separate but appear to come from a principle focus on the other side of the lens. There are three types of convex lenses depending on the shape of the surface (1). A concave lens exhibits a cave-like structure from the outside as it has a thinner middle portion and thick edges. Parallel light rays that enter the lens converge. Like a convex lens, concave lenses are used in many cases. The center of the concave lens is narrow. The incidental parallel rays on the convex lens emit convergence from the lens after refraction. This lens is used in medical (especially dental treatment), various scanners, CD, DVD players, etc. Eyes diseases like hyperopia, presbyopia, etc. When the light rays pass through the convex lens, … For this reason, a concave lens is called a diverging lens. Sign in, choose your GCSE subjects and see content that's tailored for you. Parallel light rays that enter the lens, . A convex-concave lens is a type of lens in which one surface is convex and the other is concave. The center of the concave lens is narrower, so the objects look smaller. This lens converges a bunch of parallel rays at a point. When light is refracted it changes direction due to the change in density as it moves from air into glass or plastic. Rays of light that pass through the lens are brought closer together (they converge). The incidental parallel rays on the convex lens emit convergence from the lens after refraction. Save my name, email, and website in this browser for the next time I comment. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.. But the vertex angles of these prisms are not equal. The focal length of a concave lens is negative (2). A convex lens is a lens that Converges the light rays passing through it at the focal point whereas the concave lens is the lens that diverges the beam of light passing through the lens. fig. They separate but appear to come from a principle focus on the other side of the lens. A lens that has one side is flat and the other side is convex.