Jun 10, 2016 in our class, we study two different types of lenses. The goal of the experiment is to be able to analyze ray diagrams so as to determine fundamental properties of image formation. The only difference is the reason why the light bends. An lens is a piece of glass or plastic that refracts light. Converging lens and diverging lens are one way of classifying lenses based on the behavior of the light affected by the lenses. A diverging lens will have a negative focal point where the rays. Draw ray diagrams to illustrate the formation of real and virtual images of an object by a lens 4. Lenses lenses are made of transparentmaterials, like glass or plastic. Draw scale diagrams to deduce the focal length needed for particular values of magnification. A convex lens is called a converging lens whereas a concave lens is called a diverging lens. At the front side of the lens, the rays are bent toward the normal the perpendicular to the surface because the glass is a denser medium than the air, and, at the back side of the lens, the rays. The converging lens is thicker at its center than at its edge. For a converging lens, parallel light rays will converge to a point. Diverging lenses are always concave in shape, which means the edges are thicker than the centre.
The distances from the lens to f and f are the same focal length f of the lens. A sequence is converging if its terms approach a specific value as we progress through them to infinity. Converging lenses affect parallel, diverging, and converging rays differently all three of the above ray patterns are utilized by the light microscope. Describe the action of a thin converging lens on a beam of light. Multiple two lens system with diverging and converging lens. Since the light refracts through the lens, and doesnt bounce off, like a mirror, when drawing ray diagrams, there is one.
The diverging lens is thicker at its edge than at its center. Converging lens converge and focus the light ray to meet at a single point whereas diverging lens, diverge the light falling on its surface and not meet at a single point. Converging and diverging lenses 1 2275 speedway, mail code c9000 austin, tx 78712 512 4715847 i. A convex or converging lens is shaped so that all light rays that enter it parallel to its optical axis intersect or focus at a single point on the optical axis on the opposite side of the. A point source of rays placed exactly one focal length away from a. A double convex lens, or converging lens, focuses the diverging, or blurred, light rays from a distant object by refracting bending the rays twice. A worksheet to construct ray diagrams to show where images are formed by a converging convex lens and a diverging concave lens. Two lens system example two converging lenses with focal lengths of 40cm and 20cm are placed 10cm apart. Diverging lens problems and solutions solved problems. Feedback greatly received particularly constructive ways to improve. We will finish our study of simple lenses by an examination of.
Determine the image distance, the magnification of the image, the image height, and properties of the image known. Demonstration of the optics of thin convex and concave. Mohammad kamyab javanmardi for ut environmental science institute date created. Now, mount the diverging lens on the optical bench between the converging lens and the screen as shown in fig. Instructor may wish to either use the same lens specifications focal length for each lens that the groups use or varying specifications. Convex mirrors and diverging parallel rays will be called diverging mirrors. In order to verify the theoretical relation given in eq. Converging lenses as long as the object is outside of the focal point the image is real and inverted. Aug 26, 2009 when light is coming to a diverging lens, regardless of the pattern the light from the light source makes diverging from a point, converging from a point or coming in parallel rays, the diverging lens will always make it more divergent, right. Difference between converging and diverging lens compare. Apr 28, 2008 a a converging lens with a focal length of 15cm has an object 5cm tall placed 40cm to the left of it.
It provides the thin lens equation needed to solve the problem as well as. Find the location, nature, and magnification magnification of images formed by converging and diverging lenses. Converging lens is convex lens whereas diverging lens is a concave lens. Convex converging and concave diverging lenses are drawn as, v w to understand image formation we use ray diagrams. For a diverging lens, the image is always virtual, diminished, and upright, as illustrated in the following diagram. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Although, may also be useful for other boardsalevel. This is the point in space where the light rays will converge to after passing through a converging lens. Two prisms can bend light toward the principal axis acting like a crude converging lens but cannot create a sharp focus. If the source is more than two focal lengths away from the lens, we see that the image is inverted, diminished, and real. We also learned about three simple rules of refraction for double concave lenses. As shown above, real images are produced when the object is located a distance greater than one focal length from the lens.
The first principal ray, ray 1, comes off the object parallel to the optical axis, and gets bent so that the ray appears to be coming from the focal point, as shown below. Converging lenses are thicker in the middle than near the edges, and diverging lenses are thicker near the edges than in the middle. For each case, draw the 3 principal rays to locate the image. You can see this if you apply the law of refraction to the surface where the light beam enters the glass and to the.
The focal length, f, is the distance between f and the lens. Mar 24, 2007 a diverging lens f 10 cm is located 20. Every infinite sequence is either convergent or divergent. If youre seeing this message, it means were having trouble loading external resources on our website. It is converging to the point o, and, if the concave lens had not got in the way, it would have formed a real image at o. A lens with one of its sides converging and the other diverging is known as a meniscus lens. Focal point the focal point of a lens is generally noted by the capital letter f. These can be used in applications when all intensity of light is to be focussed at a point. A lens forms an image by bending parallel rays of light that pass through it. With a converging lens, paraxial rays that are parallel to the principal axis converge to the focal point, f. Lenses converging lens diverging lens structure thicker in the middle thinner in the middle use converge. Also, virtual images cannot be obtained on a screen.
Move the screen about 15 cm farther from the object than before, and then shift the diverging lens to produce a sharp image on the screen. Brief slide show on your topic due wed nov 16 35 slides use images to enhance your slides as appropriate max 5 minutes. Converging lenses are always convex in shape, which means the centre is thicker than the edges. Needless to mention, the image formation procedure is completely distinct for the two. Convex lenses are converging lenses, and concave lenses are diverging lenses. Comparing converging and diverging sequences dummies. When the object is inside the focal point the image becomes virtual and upright. Both converging lenses and diverging lenses are very important in the understanding of optics and other related fields. Download pdf for free converging and diverging lens diagram converging lens is convex lens whereas diverging lens is a concave lens. Diverging lens problems and solutions solved problems in. The lateral magnification of the mirror or lens is the ratio.
The minus sign indicates that the focal point is virtual or the rays do not pass through the point. A thin lens has two focal points, located on the optical axis, a distance f from the center of the lens on either side of the lens. Any incident ray traveling parallel to the principal axis of a diverging lens will refract through the lens and travel in line with the focal point i. For a converging lens, the following three rays are drawn. Geometric optics converging lenses and mirrors physics lab iv objective in this set of lab exercises, the basic properties geometric optics concerning converging lenses and mirrors will be explored. Converging and diverging mirrors concave mirrors and converging parallel rays will be called converging mirrors. Diverging lenses the image is always virtual and is located between the object and the lens. Basic knowledge of converging and diverging lenses. Describe the shapes of three typical converging positive thin lenses and three typical diverging negative. C a diverging lens always produces an upright image of an object placed in front of it. It will give a virtual upright image if the object is within the focal length. All lenses are broken into two broad groups, depending on whether they focus light at a point converging lens, or spread it out diverging lens. A a converging lens always produces an inverted image of an object placed in front of it. An object outside the lens focal point forms a real and inverted image on the side of the lens opposite the object.
It is thinner at its center than its edges and always produces a virtual image. So, for a camera lens, the objects are farther and are beyond focus. A converging lens is used to form a sharp image of a candle. When the object is outside the converging lens focal point, f, the resulting image is real, inverted and on the side of the lens opposite the object.
Our procedure for diverging lenses is similar to the one presented above for converging lenses. Determination of focal length of a converging lens and mirror. Diverging lenses always form virtual imagesat any position of object. Lenses ray diagram construction worksheet teaching.
Images tracing points draw an arrow to represent the location of an object, then draw any two of the rays from the tip of the arrow. Notice from figure 1c that mass flux reaches a maximum value at this point. Using the lenses in front of you, look at different objects in the laboratory and record your observation. Do not move the positions of the object and converging for all other steps.
For lenses, the following three rays are typically used in ray diagrams. Determine the image distance, the magnification of the image, the image height, and properties of the image. Although may also be useful for other boardsalevel answer sheet available. Planoconcave a lens in which one side is concave and the other is plano.
Converging lenses are divided into three cases, which depend on the source location. If the lower half of the lens is covered by a piece of paper, the a. B a diverging lens always produces an image that is larger than the object. This physics video tutorial focuses on a multiple two lens system that contains a diverging lens and a converging lens. Apply the lensmakers equation s equation to find parameters related to lens construction. A converging lens is a lens that converge a beam of light to a point whereas diverging lenses make. Convergent and divergent sequences video khan academy. Positive meniscus a converging lens where one side is concave and the other convex. A lens forms an image by bending rays of light that pass through it. Start studying chapter 30 converging and diverging lens lenses. While diverging lenses always produce virtual images, converging lenses are capable of producing both real and virtual images. Converging and diverging lenses 2 2275 speedway, mail code c9000 austin, tx 78712 512 4715847 i.
This is shown with the geometrical ray diagram of figure 4. Converging and diverging lens are shown in the figure. Each of a lens two faces is part of asphere and can be convex or concave if a lens is thicker at the center than theedges, it is a convex, or converging, lenssince parallel rays will be converged tomeet at the focus. Shapes of lenses the shape of a lens can be understood by con sidering a lens to be a large number of portions of prisms, as shown. Convex converging and concave diverging lenses are drawn as. Which lens magnified the object and which made it look smaller. The focal length f is positive for converging lenses, and negative for diverging lenses.
You can perform the following experiment to know that convex lens converges the light rays and concave lens diverges the light rays. Lenses are usually made either of glass or clear plastic and are ground and polished to have spherical surfaces. If the focal length is in metres, this gives the optical power in dioptres inverse metres. Jun 28, 2012 converging lens and diverging lens are one way of classifying lenses based on the behavior of the light affected by the lenses. Thin lens equation focal length of a converging lens. Advanced knowledge of converging and diverging lenses. Converging and diverging lenses flashcards quizlet.
If a camera uses a converging lens, wouldnt it mean that. The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A convex lens gives a real, inverted image if the object is outside the focal length of the lens. Pdf on nov 25, 2014, deborah sand and others published lenses find. Converging lenses form real inverted images if x o f and virtual upright images if x o and the center curvature are on the opposite sides of the lens. A 5cm high object is placed 15 cm from a 30cm focal length diverging lens. It doesnt reflect, like in the mirrors, it refracts through the lens. Converging and diverging behaviour definition if refracted rays converge to a single point after refraction, then this is called as converging behaviour of the lens. If the thickness of the lens is much less than the distance from the lens to each focal point. In the problems you encounter, the object will either be within the focal length of the lens or outside of the focal. Which of the following statements are true for images formed by thin lenses. Demonstration of converging and diverging action of lenses example use a card board ready made shirt box like the one used to study the laws of reflection using a comb and torch.
But, converging lenses do so only for objects closer than its focus. Several varieties of two basic forms of lenses exist. A 2cm tall object is located 15cm from the 40cm focal length lens as shown in the figure. To the right, 30 cm away, is a converging lens of focal length 10cm. Note that a converging lens has a thicker waist, whereas a diverging lens has a thinner waist. A lens placed in the path of a beam of parallel rays can be called a diverging lens when it causes the rays to diverge after refraction. Negative meniscus a diverging lens where one side is concave and the other convex. Earlier in lesson 5, we learned how light is refracted by double concave lens in a manner that a virtual image is formed.
854 156 670 344 309 2 1356 1549 278 979 1501 568 651 1606 167 78 1046 576 1308 1434 620 140 1521 193 1471 935 769 917 274 1288 37 631 1408 200 351 1310 827 1157 94 1360 845