Of the two types of lenses convex and concave, the concave lenses are used less frequently. A concave lens will always produce diminished, upright and virtual image of the object in front of it. If an object is placed in front of a convex lens, the nature of the image formed depends on where the object is placed. Displaying top 8 worksheets found for concave and convex lenses. Some of the worksheets for this concept are diverging converging lens work, concaveconvex s1 identifying shapes, converging diverging lenses ray diagrams, name box score date ap physics work 14 chapter 24, refraction convex and concave lenses, exploration of optics converging and diverging lenses, ray.
Demonstration of the optics of thin convex and concave lenses. One mark questions convex mirror for seeing traffic at the. This report presents a lab experiment that hopes to introduce and familiarise. Image formation in a convex lens can be explained with the help of three principal rays shown in the figure. Concave and convex lens uses difference between concave. But the nature of the image produced by a these lens depends upon the position of the object. Image formation by convex and concave lens ray diagrams. A thin convex lens can be characterized by its focal length f, the object distance, d o. To explore the difference between convex and concave lenses and to determine their focal lengths.
Convex lenses are also known as converging lens since the rays converge after falling on the convex lens while the concave lenses are known as diverging. If the lens is biconvex or plano convex, a collimated beam of light passing through the lens converges to a spot a focus behind the lens. Most devices that control light have one or more lenses in them some use only mirrors, which can do most of the same things that lenses can do. One such difference is the structure of convex lens is like, thicker at the centre and thinner at the edges.
The polarity of most lenses reported so far, that is, either positive convex or negative. It will give a virtual upright image if the object is within the focal length. Figure 315 defining points for concave and convex mirrors. Each mirror has a radius of curvature r which is in.
When an object is placed at infinity, the real image is formed at the focus. Convex concave meniscus lenses can be either positive or negative, depending on the relative curvatures of the two surfaces. So just remember, concave has the word cave in it so i always imagine that its kind of caving inwards caving inwards its a little bit of an exaggerated drawing but you get. Oct 24, 20 geometric optics intuition with mirrors and lenses concave convex diverging converging doc physics duration. Difference between convex and concave lens with figure. To investigate the image formed by a certain thin convex lens and to determine its focal length. Dec 08, 2018 eight important differences between convex and concave lens are compiled in the article in tabular form.
Convex lens uses, examples, definition, ray diagram, formula. Light ray rules for convex lens and concave lens are discussed. A convex lens is a converging lens when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus the distance between the principal focus and the centre of the lens is called the focal length. Describe the shapes of three typical converging positive thin lenses and three typical diverging. The size of the image is much smaller as compared to that of the object. Curving inward, concave lenses cause light to spread out, resulting in a smaller image for the viewer. When a ray, passing through focus strikes concave or convex lenses, the reflected ray will pass parallel to the principal axis. Uses of the concave mirror and the convex mirror in our daily life.
Slide the convex and concave lenses apart to observe the effect of a combination of two lenses. Real and virtual images in question 2, students work with the bi concave and bi convex lenses to see that they can actually make a. Conversely, the concave lenses are thinner at the centre and thicker at its edges, in structure. Curved mirrors concave and convex linkedin slideshare. Lenses concave and convex apparatus selection of lenses, collimated light source, e.
Concave lenses concave lenses always produce upright, virtual images. They should try to describe any images they form in terms of magnification, upright or inverted, real or virtual. In this article, we will learn about image formation by concave and convex lenses. Mar 03, 2019 convex and concave lenses are spherical lenses. Convex lenses are used for focusing light rays to make items appear larger and clearer, such as with magnifying glasses. A concave lens contains at least one inwardlycurved surface, and it is also referred to as a divergent lens.
A lens with one convex and one concave side is convex concave or meniscus. Use the thin lens equation to find the distance of the image. The focal length is measured from the center of the lens to the focal point. Define the following terms in relation to concave spherical mirror. The focal length of a convex lens is positive, while that of a concave lens is negative. Convex lens, optical bench, light source, target image slide, lens mounts, and screen. Lenses convex converging lens laws of refraction and reflection can be used to explain how lenses and mirrors operate parallel rays e. Rays of light that pass through the lens are brought closer together they converge. Concave and convex lenses image formation curvature.
Parallel rays of light passing through a thin convex lens cross at the focal point of the lens. What are the uses of concave and convex lenses in daily life. Focal length f f is positive for converging and negative for diverging lenses. It can form both real and virtual images depending on where the light is coming from. Lets explore the ray tracing technique to figure out the properties of images when things are kept in front of a concave or a convex mirror. They should determine from the image produced whether a lens is concave or convex. Surface topography and refractive index profile dictate the deterministic functionality of a lens. Use this quiz and worksheet to gauge your comprehension of a concave lens. Convex lens screen purpose to determine the focal length of a thin lens and to explore the difference between convex and concave lenses and to determine their focal lengths. Properties of the formed images by convex lens and concave. What are the uses for concave lenses and convex lenses. Curvedspherical mirror a curved mirror is a mirror with a curved reflecting surface. We look at the image formation by these spherical lenses using ray diagrams. Convex lenses are converging lenses, and concave lenses are diverging lenses.
On the contrary, the image formed by the concave lens is erect, virtual and smaller, than the object. Convex and concave lenses purpose in this experiment, you will explore the difference between convex and concave lenses and determine their focal lengths. The lab activity requires the use of concave and convex lenses. This is a fun and engaging way to practice determining the differences between concave and convex lenses. Focal length f is positive for converging and negative for diverging lenses. It is this type of lens that is most commonly used in corrective lenses. Conversely, a positive meniscus lens has a steeper convex surface and is thicker at the centre than at the periphery. Concave lenses are used for correcting myopia or shortsightedness. A negative meniscus lens has a steeper concave surface and is thinner at the centre than at the periphery.
Weve talked a lot about convex lenses, so i thought i would do a quick video on concave lenses, although there arent as many combinations of what a concave lens can do. Convex converging and concave diverging lenses are drawn as. A convex lens gives a real, inverted image if the object is outside the focal length of the lens. When an object is placed behind the center of curvature. This is explained with the help of ray diagrams as follows.
I use simple small ones that are cheap and easy to buy. Place the convex lens in the path of the five rays. Oct 12, 2015 therefore, convex lenses are also called converging lenses. Draw a ray diagram and use the information from the ray diagram to fill in the box. Generally, a convex lens forms a real image, but it can also create a virtual image when the object is in the middle of the focus and optical centre.
Topics youll need to understand include uses for lenses and types of lenses. Convex lenses are also known as converging lens since the rays converge after falling on the convex lens while the concave lenses are known as diverging lenses as the rays diverge after falling on the concave lens. Concave lenses video geometric optics khan academy. R 11 and r 2 2 are positive for convex outward surface and negative for concave surface. In addition, you need to have a small object penny, pair of dice, etc and a large object cabinet, door, tv, etc for students to examine. Sep 26, 2015 the concave lens is known as the diverging lens because it diverges the rays after they pass through it, the image formed by the concave lens is a virtual image because it can not be received on a screen. Apparatus selection of lenses, collimated light source, e. Acces pdf light refraction and lenses answers light refraction and lenses answers eventually, you will extremely discover a additional experience and capability by. Convex lenses, geometrical optics from alevel physics tutor. Oct 10, 2018 it is best in our daily life to know that camera make image small how,projector make image larger than object,how we can we see distamt objects like moon,stars in our dialy life many of the girls and man wearing lenses,copier projector for this k. The converging lens is thicker at its center than at its edge. Convex and concave lenses jonny nelson introduces an animated explanation of lenses a lens is a shaped piece of transparent glass or plastic that refracts light.
In mirrors, images are formed through reflection but lenses form images through refraction. Generally, a convex lens forms a real image, but it can also create a virtual image when the object is. The surface may be either convex bulging outward or concave bulging inward. If an object is placed in front of the lens at a distance less than its focal length, the image formed is upright, enlarged and virtual. Theory when parallel light rays pass through a thin lens, they emerge either converging or diverging. To understand ray diagrams it is important to know something about images. The point where the converging rays or their extensions cross.
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