Physics Help Forum Lenses system

 May 2nd 2016, 12:54 PM #1 Member   Join Date: Mar 2016 Location: Manchester Posts: 37 Lenses system I am having some trouble understanding a question involving a lens system, which is as follows: A 20cm tall object is placed 80cm in front of a -6.75D lens. A second lens of power +3.00D is placed 7.5cm behind the first lens. The lens system is aligned so that the lenses are co-axial. Calculate the position and size of the image produced, and state the nature of the image. I first tried treating each lens separately to determine the image position and found a value for the image position di = -50cm for the full system but I'm not sure if this is correct. The nature if I found for the image was that it was virtual, magnified and upright. I am hoping maybe someone can verify my results. Would be a great help indeed
 Sep 26th 2016, 04:21 AM #2 Junior Member   Join Date: Sep 2016 Location: London Posts: 18 A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or moulded to the desired shape. A lens can focus light to form an image, unlike a prism, which refracts light without focusing. Devices that similarly focus or disperse radiation other than visible light are also called lenses, such as microwave lenses, electron lenses or acoustic lenses. https://www.boundless.com/physics/te...nses-614-5930/

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