Rules for drawing ray diagrams for converging lenses. Optical centre is where the principle axis meets the lens centre. All the distance measurements are done from pole of the. Instead of drawing the 3rd ray through the center of curvature, draw the third ray through the center of the lens, it will pass straight through, no refraction this is the. Draw a ray that travels parallel to the axis which refracts as if it came from the focal point in front of the lens. The image is always formed inside the focal length of the lens. We have seen that when light rays pass through a lens, they refract in a number of different ways. Rays that come in parallel to the principal axis go out through the outgoing focus. F f 1 2 3 draw a ray straight through the centre of the lens.
In this article i am introducing a simulation i use to teach mirrors and ray diagrams in grade 10 optics. Bubble lenses united way california capital region. Aug 20, 2015 description of how to draw ray diagrams for converging lenses for grade 10 science. A ray diagram showing the image produced by the second lens. Virtual images real images cannot be formed on a screen. Ray diagram for a convex lens figure below shows how light rays are focused by a convex lens. Notes,whiteboard,whiteboard page,notebook software,notebook, pdf,smart,smart technologies ulc,smart board interactive whiteboard created date. The other ray of light always passes through the focal point of the lens. Concave lenses, geometrical optics from alevel physics.
The following represents a system of two lenses, the first a convex lens with focal length f1 30 mm, and the second a concave lens with focal length f2 60 mm. With a concave lens, the image will always be diminished, the right way up and virtual. The prisms have their bases towards the optical centre. Ray diagrams, use ray diagrams to find magnification and locate objects, images, or lenses when appropriate other information is given for twolens systems. In addition you may be asked to calculate the lateral magnification. Although may also be useful for other boardsalevel answer sheet available. Ray diagrams for thin lenses ray diagrams are essential for understanding the overall image formation three rays are drawn the first ray is drawn parallel to the first principle axis and then passes through or appears to come from one of the focal lengths the second ray is drawn through the center of. Draw scale diagrams to deduce the focal length needed for particular values of magnification. Ray tracing lenses diverging lens focal lengths less than zero 1.
The ray diagram was then completed and the students took. Apr 11, 2020 in mirrors, images are formed through reflection but lenses form images through refraction. Convex lenses, geometrical optics alevel physics tutor. Rays parallel to the axis are reflectedrefracted through focal point 2. A selection of worksheets that i have written and collected together to take students through the process of constructing the ray diagram for converging and diverging lenses.
Feedback greatly received particularly constructive ways to improve. Sign conventions combination of lenses cameras the human eye, lenses and magnifiers telescopes microscopes thin lenses lenses are refractive optical devices with two spherical sides. Rays passing through the focal point reflectrefract parallel through the axis. That is why i wanted to see if a corrective lens is able to make the ray s parallel at both the maximum, minimum, and ideal positions. Image formation by convex and concave lens ray diagrams. The first principal ray occurs when the light comes in parallel to the principle axis, it goes out through the focus. The second principal ray occurs when light comes in through the focus, then it.
Convex lenses object between the lens and focal point. In preparation for our exam, i handed out this practice sheet. Notes,whiteboard,whiteboard page,notebook software,notebook,pdf,smart,smart technologies ulc,smart board interactive whiteboard created date. Ray optics and optical instruments class 12 notes pdf download. Parallelray method step 2 image from step 1 becomes object for step 2 after producing this object, lens1 one can be ignored object can be real or virtual virtual in this case object can be real even if image from lens 1 is virtual trace any two of the three rays shown through tip of object to find tip of final image. Image formation in a convex lens can be explained with the help of three principal rays shown in the figure. Make light rays move closer together converge or move apart diverge. In each diagram, an upward arrow has been provided as the object. Use ray tracing to determine the position of the final image, given the object position. Using the law of reflection, complete the raytrace diagram for the four rays a.
Light reflection and refraction 161 let us recall these laws i the angle of incidence is equal to the angle of reflection, and ii the incident ray, the normal to the mirror at the point of incidence and the reflected ray, all lie in the same plane. With these new terms explained, the teacher will demonstrate the basic rules underlying ray diagrams for both convex and concave lenses. Drawing lens ray diagrams authorstream presentation. Students should also know how to determine the focal length of a lens and some important optical instruments like projector, single lens camera and magnifying glass. Converging and diverging lenses 2 2275 speedway, mail code c9000 austin, tx 78712 512 4715847 i. Describe the properties of an image produced by a concave lens. Concave lenses the above is true for an object in all positions. The description is applied to the task of drawing a ray diagram for an object located beyond the 2f point of a double convex lens. In an astronomical telescope, which uses two converging lenses, the distance between the lenses is the sum of the two focal lengths. Feb 27, 2015 a worksheet to construct ray diagrams to show where images are formed by a converging convex lens and a diverging concave lens. Nov 16, 2012 we use ray diagrams, and then estimate distances based on the scale of the diagram. Draw ray diagrams to illustrate the formation of real and virtual images of an object by a lens 4. After completing this lab, you will be able to explain how lenses work, explain the difference between convex and concave lenses, draw ray diagrams to analyze the image produced by a lens, and.
Ice use a water filled cylinder and a bubble to create convex and concave surfaces. The ray diagrams for concave lenses inside and outside the focal point give similar results. Since the light refracts through the lens, and doesnt bounce off, like a mirror, when drawing ray diagrams, there is one difference. Use lens equation to find the final image m i 2o i 2i 1 i 1o m 1 x m 2. Object is between the focal point and 2x the focal length. I use these in my conceptual physics classes and ap physics. I wonder if there is not a mistake for the lens experiment with letters. Answer e is incorrect because it is possible to combine concepts of ray diagrams to select a correct solution out of the options. Converging convex lenses these lenses are thicker in the middle than at the edge, and cause parallel beams of light to converge. Ray diagram convex lens2 object beyond 2f, cbse science,cbse physics,cbse grade 10,icse physics,focus,pole,principal axis,igcse physics,igcse grade 9,igcse.
New cartesian sign convention for spherical mirrors. Outline reflection mirrors plane mirrors spherical mirrors concave mirrors convex mirrors refraction lenses concave lenses convex lenses j. Concave lens and ray diagrams examples, solutions, videos. Lenses ray diagram construction worksheet teaching resources. Since lenses pass light through them unlike mirrors it is useful to draw a focal point on each side of the lens for ray tracing. Ray diagrams are constructed by taking the path of three distinct rays from a point on the object. Where is the final image as shown, two converging lenses, each with a focal length of 10cm, are separated by 50cm. Only the bottom ray is correct because it should not refract when it passes directly through the middle of the lens. Either the first focal point of the second focal point. Since the lenses are symmetrical in the x and y directions, i only have to look at it in terms of one axis. Lens equation use the thinlens equation to find magnification and locate. Concave lenses draw a ray diagram to show how an image is formed by a concave lens. Rays that come in through the incoming focus go out.
The method of drawing ray diagrams for double convex lens is described below. That is, they diverge parallel rays of light from a focus, producing a virtual image. Philosophers thought light was made up of streamers emitted by the eye making contact with an object others thought that light was made of particles that traveled from the eye even others thought that light traveled as waves. A convex lens will converge parallel light rays to a point called the focal point of the lens. The line through the centre of the lens is called the priil iinciple axis. When the ray reaches the lens plane it bends away from optical axis so that the ray looks like it originates from the focal point a. This collection of 48 slides leads students slowly and clearly through all the major ray diagrams for lenses and mirrors in a c. Prisms divert or refract light rays toward the direction of their bases. Chapter 24 refraction and lenses page 24 21 figure 24. The incident ray, normal and reflected ray all lie in the same plane.
The angle of incidence is always equal to angle of reflection. This is explained with the help of ray diagrams as follows. Dec 25, 2015 trick to drawing ray diagrams for converging lens. To understand ray diagrams it is important to know something about images. Imaging with two lenses graphical methods parallelray method, find intermediate image, use as object for next lens virtual objects obliqueray method, lenstolens, no need to find intermediate image mathematical methods find intermediate image, use as object for next lens lenstolens sequential raytracinglater. Ray diagrams three rays leave one point on an object.
Ray diagrams can be one of the trickiest things to really get in introductory physics. In addition to the above, you can switch to a mirror by tapping the lens button at the top of the screen. Rays passing through the center of lens are undeflected 3. Pick a point on the top of the object and draw three incident rays traveling towards the lens. Our exam board only require two rays to be drawn but if you want to research into it further, please refer to the helpful web pages below. Ray diagram convex lens 2 object beyond 2f youtube.
Although not frequently countered in examination, lens formula allows students to check their answer from ray diagrams. A worksheet to construct ray diagrams to show where images are formed by a converging convex lens and a diverging concave lens. A cameras is essentially a converging lens with a short focal length. A ray of light is an extremely narrow beam of light. There is one ray of light passing through the center of the lens. The ray in geometric optics is an abstraction useful for approximating the paths along which light propagates under certain circumstances the simplifying assumptions of geometrical optics include that light rays.
Here are some useful rays in determining the nature of the images formed by converging and diverging lens. It presents the six different situations above, with an appropriatelysized mirror or lens, with focal and center points already labeled, and an object already drawn. Thin lenses lens makers equation ray diagrams and thin lens eqs. For your convenience, blank diagrams will objects already provided are located on this page in ie use landscape mode with margins of 0. Although, may also be useful for other boardsalevel. There are a lot of pieces that have to be done just so and the rules seem arbitrary. Focal point and focal length ray diagram for lenses. Draw a ray in line with the focal point, with the reflected ray parallel to the principal axis. Chapter assessment 30justinna licea flashcards quizlet. There are three convenient rays commonly used in ray diagrams to estimate the position of an image.
In this lab, you will construct the six special ray diagrams for converging lenses. Instructor may wish to either use the same lens specifications focal length for each lens that the groups use or varying specifications. Ray diagrams 4 of 4 concave lens and convex mirror shows how to draw the. To explain the experiment in the observational experiment table 22.
In mirrors, images are formed through reflection but lenses form images through refraction. The following diagrams show the ray diagram for a concave lens. Thin lenses solve problems involving a single thin lens by drawing ray. Types of lenses there are two types of basic lenses. A convex lens may be considered to be made up of two prisms and a solid glass block in the centre. It presents the six different situations above, with an appropriatelysized mirror or lens, with focal and. A ray passing through the center of any lens continues in a straight line. Pdf on nov 25, 2014, deborah sand and others published lenses find, read and cite all the. Lenses ray diagram construction worksheet teaching. Describe the action of a thin converging lens on a beam of light. A mirror whose shape is part of a circle, which is defined by. Draw a ray travelling to the vertex and reflecting at the same angle.
All four types of concave lens are diverging lenses. Students will be asked to follow along on their worksheets. Elaboration students will return to their original groups to conduct the elaboration portion of their experiments. When you focus a camera, you adjust the distance of the lens from the film. To understand concave and convex lenses and to make ray diagrams three rules for ray diagrams. Phet has a simulation for refraction and one for lenses but there is nothing for mirrors, so i developed this simulation for grade 10 optics. Instead of drawing the 3rd ray through the center of curvature, draw the third ray through the center of the lens, it will pass straight through, no refraction this is the middle ray in the diagram below. All lenses and mirrors can use ray diagrams to find images.
Draw a ray parallel to the principal axis, with the reflected ray reflecting in line with the focal point behind the mirror. A lens is any glass, plastic or transparent refractive medium with two opposite faces, and at least one of the faces must be curved. Jun 23, 2015 122 ray diagrams lenses in this video paul andersen explains how ray diagrams for lenses can be used to determine the size and location of a refracted image. Ray diagram for an experimental lens systems physics forums.
This is two worksheets to practice ray diagrams for lenses. Geometrical optics, or ray optics, is a model of optics that describes light propagation in terms of rays. Lenses have focal points on either side because light shines thro h either side shines through either side. Microsoft word six ray diagrams mirrors and lenses author. Concave lenses, geometrical optics from alevel physics tutor. Image formation in a convex lens can be explained with. Focal length and object height are both controlled with the sliders. Rays emerge from a single point, with number controlled by the ray density slider.
We use ray diagrams, and then estimate distances based on the scale of the diagram. A parallel beam of rays emerges from a linesegment, with density controlled by the ray density slider. Description of how to draw ray diagrams for converging lenses for grade 10 science. Draw a ray from top of object through center of lens. The refraction at the first surface is balanced by the refraction at the second surface. Describe these three rays in terms of their orientation with respect to the principal axis and focal points.
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