equiconvex lens (made from a glass of known refractive index) and an adjustable object needle APPARATUS: A convex lens‚ an optical needle‚ a plane mirror‚ a clamp stand‚ a spherometer‚ a plumb line‚ metre scale‚ water and turpentine oil Theroy : Let’s add small amount of water on a flat‚ plane surface and place a convex lens over it. This forms a plano-concave lens of water between the lower surface of convex lens and plane mirror. Let f 1 and f 2 are the focal lengths of water lens and convex lens respectively
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Refraction in Biconcave Lens Now let’s investigate the refraction of light by double concave lens. Suppose that several rays of light approach the lens; and suppose that these rays of light are travelling parallel to the principal axis. Upon reaching the front face of the lens‚ each ray of light will refract towards the normal to the surface. At this boundary‚ the light ray is passing from air into a more dense medium (usually plastic or glass). Since the light ray is passing from a medium in
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the Thin-Lens Equation: Where f is the focal length of the lens‚ do is the object distance and di is the image distance. From the Thin-Lens Equation we are able to mathematically see and understand many interesting and valuable situations that arise when working with lenses. When the object is the same distance from the lens as the image‚ for instance‚ we can easily verify that the focal length must equal half the image (object) distance or if the object is very far away from the lens (at infinity)
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small plane mirror and wooden clamp Convex lens and holder. two mounted pins‚ metre rule or optical bench. Method: Place a mounted pin at a distance from the convex lens greater than the focal length so that a real image of the pin is produced. Locate this image by means of the second pin. Place the convex mirror between this second pin and the lens and adjust its position until the light reflected from the mirror passes back through the lens and forms an image coincident with the object
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are perceived by the eye and the lens is the part that makes this possible. Objects which are close to the eye are seen by the eyes’s lens becoming thicker and more bulbous in order to create a lens with a higher refractive index for detailed sight‚ i.e. for close work like sewing . The CILIARY MUSCLE contracts‚ pulling the Ciliary process and Choroid towards the lens. Tension is therefore released ob both the SUSPENSORY LIGAMENTS and the lens and this makes the lens able to focus the light rays
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he aqueous humor‚ from the aqueous humor to the lens and from the lens to the vitreous humor. Light spreading out from one point on an object can therefore be focused on a particular point on the retina. Syllabus | Exams | Websites | Resources | Exam techniques | Teachers Biology Home > Biology > Options > Communication > Communication: 3. Refraction of light in the eye 9.5 Option – Communication: 3. Refraction of light in the eye Syllabus reference (October 2002 version) 3. The clarity
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radius of curvature of 3m. If a bus is located at 5m from this mirror‚ find the position‚ nature and size of the image. 04. What are the various factors of refraction of light? 05. (a) Define Power of a Lens. Write its SI unit. (b) Find the focal length of a lens of power 2 D. What type of lens is this? ONE MARK QUESTIONS 01. For what position of an object a real and diminished image is formed by a concave mirror? 02. What is the relation between the focal length and radius of curvature of
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1. This question is about lasers. (a) With reference to the light waves emitted by a laser‚ state what is meant by the terms (i) monochromatic. ........................................................................................................................... ........................................................................................................................... (1) (ii) coherent. ...............................................................................
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water for tank 2=1.35 2. What is the focal length of the lens used in section 1.3 “Focal Length” of your manual? Can you deduce from the image seen‚ if the lens used was converging or diverging? The focal length of the lens used is calculated to be 31 mm. The lens used in the experiment was a converging lens as the image was 3. Calculate the focal length of the given converging lens based on the measurements of s and s ’ and thin lens equation. Tabulate your results (for all the three trials)
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And that determines what kind of lens the optometrist will work with. What are the eye conditions? If seeing: * Light rays Light rays Retina Retina Retina Retina Light rays Light rays Focal point Focal point Far blurry objects (near-sightedness) use spherical corrective lenses with negative power. EYE EYE (Near-sightedness) correction (Near-sightedness) correction Negative spherical lens Negative spherical lens Focal
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