Looking through both lenses, using the 10cm lens as an eyepiece lens, view a distant object through both lenses. Fredos full aperture, 5mm why are lenses so complex. The to go version of the teacher toolkits are provided with the thought that physics teachers might want to have a backtoback copy of a toolkit on a single sheet of paper in order to include in their printed files. By taking readings of image and object distances for different positions, a graph can be drawn. Converging lenses, like those normally found in reading glasses, have positive refracting powers. The physics classroom also sells a product called the solutions guide that provides purchasers with the source documents microsoft word files, answers and solutions, and a broader set of licensing rights. Kids learn about lenses and light in the science of physics including concave, convex, converging, diverging, focal point, meniscus, and plano lenses. A telescope with an objective lens with a diameter with a wavelength of light can barely resolve two objects with an angular separation of using. Worksheets are synchronized to readings from the physics classroom tutorial and to sublevels of the minds on physics internet modules. Qualitative and quantitative questions about image formation by lenses. Introduction to physics 1112k lab makeup form how to open phet java files on apple computers. Focal length of convex lensb11 lab report objectives of the experiment.
That is, light rays from one point on the object actually cross at the location of the image and can be projected onto a screen, a piece of film, or the retina of an eye, for example. To determine the focal length of a spherical convex lens by lens formula method by lens replacement method. Crossgrade comparison of students conceptual understanding with lenses in geometric optics g. Voiceover if i had been handed this problem on a physics test i probably would have freaked out. This looks really intimidating but its actually not that bad. Pdf optical images due to lenses and mirrors researchgate.
A convex lens gives a real, inverted image if the object is outside the focal length of the lens. Manuals for each lab are available as either doxcx or pdf files, data in xlsx files. The same sort of rules apply, just with a few modifications. Another property of lenses is magnification, which represents how large or small an object looks when viewed through a particular lens. And think about how they transmit or refract light. In working with lenses, there are three important quantities to consider. It is proven in introductory physics textbooks1 that the image and. Two prisms can bend light toward the principal axis acting like a crude converging lens but.
This book provides an introduction to the eld of optics from a physics perspective. A magnifying glass is just a doubleconvex lens in thinlens speak, its a. Crossgrade comparison of students conceptual understanding. A compound microscope has two convex lenses, separated by 10. Geometric optics and introduction to interference ch.
Keep in mind that for an object to be considered a lens it must be made of a transparent material. So remember, concave means it opens inward, like a cave. For example, the following information will put north koreas uranium enrichment program in a less threatening. Concave lenses, geometrical optics alevel physics tutor. The overall idea of how were going to approach is this. A ray parallel to the lens axis passes through the far focus of a converging lens or appears to come from the near focus of a diverging lens. Screen placed behind a magnifying glass which is in front an open window.
Spherical lenses problems the physics hypertextbook. Lenses are curved glasses or transparent materials. Weve talked a lot about mirrors, in particular parabolic mirrors, that reflect light. Students commonly find the field of physics difficult. Answer e is incorrect because a ray diagram will show that. In this experiment, we have chosen two methods to find out the focal length of a. In this experiment, we have chosen two methods to find out the focal length of a spherical lens. The application of the thin lens equation and the magni. Lenses lenses refract light in such a way that an image of the light source is formed. The object distance is the distance along the axis of the lens to. The image produced is virtual, upright, diminished and on the same side of the lens as the object back to top.
The separation distance between the two objects, we will call this, and the distance to the objects from the telescope objective can be related to the tangent of that angle, you are far away from the lights and this angle is very. Keep in mind that for an object to be considered a lens it must be made of a transparent material that has an index of refraction higher than air. The physics of nuclear weapons while the technology behind nuclear weapons is of secondary importance to this seminar, some background is helpful when dealing with issues such as nuclear proliferation. The curriculum corner consists of a collection of downloadable pdf files designed to complement the resources at the physics classroom. The focus of the concave lenses is where rays parallel to principal come from. One of the subjects with which they have difficulties is optics within a physics discipline. The image formed in figure 7 is a real image, meaning that it can be projected. Use raytracing techniques tracing techniques to construct images formed by converging and diverging lenses. Bc objectives to examine the nature and location of images formed by lenses. 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. Optical bench, light box, lenses, lens holders, illu.
Convex lenses, geometrical optics from alevel physics tutor. Find the location, nature, and magnification magnification of images formed by converging and. With a converging lens, paraxial rays that are parallel to the principal axis converge to the focal point, f. Optical bench, light box, lenses, lens holders, illu minated target object, white screen with scale, mirror. Lenses remembering the basics of mirrors puts you half ways towards fully understanding lenses as well. Lenses in optics applications types of lenses physics. To learn the quantitative use of the lens equation, as well as how to determine qualitative properties of solutions. Solution answer a is incorrect because an image will only form in front of the lens when the object is inside the focal length of the lens. Diverging lenses, like those worn by people with myopia or nearsightedness, have negative refracting powers. Determine the focal length of a diverging lens using the lensmakers equation. The physics convex lenses are converging lenses, and concave lenses are diverging lenses.
A lens is a transmissive optical device that focuses or disperses light beams by means of refraction. Magnification is defined as the ratio of an objects image height, h, to its actual height, h. Frankl your own mind is a sacred enclosure into which nothing harmful can enter except by your promotion. Its a classic example of a two lens system and overall, before we get lost in details here. When light is incident on the lens at an angle, this will bend the light due to refraction. So lets talk about lenses, a lens is a curved piece of glass or some other transparent material that were going to use to focus light and generate some images. A lens can focus light to form an image, unlike a prism, which refracts light without. The focal length f of a lens can be found quite accurately by moving an illuminated object infront of a lens so that an image is cast on a screen. The focus of convex lenses is where rays parallel to principal axis go. Rays of light that pass through the lens are brought closer together they converge. Real images, such as the one considered in the previous example, are formed by converging lenses whenever an object is farther from the lens than its focal length. No annoying ads, no download limits, enjoy it and dont forget to bookmark and share the love. Refraction and lenses the following downloadable pdf files represent a collection of classroomready worksheets pertaining to the topic of refraction and lenses. As of today we have 110,518,197 ebooks for you to download for free.
Converging and diverging lenses 1 2275 speedway, mail code c9000 austin, tx 78712 512 4715847 i. Experimentally measure the image distance and con firm the thin lens equation. Explore the difference between converging and diverging lenses and determine their focal lengths. Spectacle used for correcting long and short sight. Apply the lensmakers equation s equation to find parameters related to lens construction. When parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus. Physics 126 laboratory manual experiment 3 lenses and images who shall teach thee, unless it be thine own eyes. Experimentally determine the focal length and magnification of a convex converging lens. Answer b and c are incorrect because, while the image will be formed at a multiple of f to the right of the lens, a ray diagram will show that it does not form at 12f or f. The pdf files come in two basic forms as an entire packet collection of pages or as individual pages. It will give a virtual upright image if the object is within the focal length. This is true for movie projectors, cameras, and the eye. Investigate and verify the thin lens and magnification equations.
Use raytracing techniques to locate images formed by thin lenses. Lenses science and mathematics education research group supported by ubc teaching and learning enhancement fund 201220 department of curriculum and pedagogy a place of mind f a c u l t y o f e d u c a t i o n. Once you have the image in sharp focus, take measurements for the object distance, s, the image distance,s, and the height of the image, h. The toolkit to go pdf on the topic of image formation by lenses is displayed below. A simple lens consists of a single piece of transparent material while compound lenses consist of several simple lenses arranged along with a common axis. A lens is a curved piece of glass or plastic designed to refract light in a specific. Mohammad kamyab javanmardi for ut environmental science institute date created. Howard university department of physics and astronomy spring 2020 syllabus course. Solving problems involving thin lenses and images smu. Use the lensmakers equation to determine the focal length of a thin lens.
Pdf files are available for every unit covered at the physics classroom tutorial. What i want to do now is talk about lenses, or talk about what a lens is. Using a ruler or other straight edge and the ray tracing methods described in this section, locate and draw the image of the pencil. The physics classroom grants teachers and other users the right to print this pdf document and. Gently adjust the eyepiece lens position until the image of the object is clear and focused.
A convex lens is thicker at the centre than at the edges. Go out into the hallway and arrange the two converging lenses so that the objective lens, the big one is in front of the other and they share the same optical axis similar to the diagram for the keplerian telescope on p. Lenses lenses are made of transparentmaterials, like glass or plastic. A case 1 image is formed when do f and f is positive, as in figure 10a. Waves and optics lenses lenses virtual image produced by real images focused on a magnifying glass placed closed to an object.
Everyones eyes are different and the eyepiece must be adjusted individually. For each object position, answer the following questions about the. To measure and compare the focal lengths of some lenses using different methods, and to determine the magnification of a simple telescope. Figure 8 shows how such an image would be projected onto film by a camera lens. There is no image without a lens as rays diverge in all directions. It focuses primarily on the wave and ray descriptions of light, but also includes a brief introduction to the quantum description of light. The greater the power a pair of eyeglasses or contact lenses has, the worse is the vision of the person prescribed them. Theory lenses are frequently found in both nature and technology, wherever it is useful to form an image. The focal length, f, is the distance between f and the lens. Phy 112l activity 10 university of southern mississippi. Its a classic example of a two lens system and overall, before we. So lets see how it goes, suppose that ive got an object out here in air and then ive got a piece of glass thats curved outward like this in a convex way.
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