ImagesSlide 2Two Types of ImagesA Common MiragePlane Mirrors, Point ObjectPlane Mirrors, Extended ObjectPlane Mirrors, Mirror MazeSpherical Mirrors, Making a Spherical MirrorSpherical Mirrors, Focal Points of Spherical MirrorsImages from Spherical MirrorsLocating Images by Drawing RaysProof of the magnification equationSpherical Refracting SurfacesThin LensesImages from Thin LensesLocating Images of Extended Objects by Drawing RaysTwo Lens SystemSlide 18Slide 19Slide 20Optical Instruments, Simple Magnifying LensSlide 22Optical Instruments, Refracting TelescopeThree Proofs, The Spherical Mirror FormulaThree Proofs, The Refracting Surface FormulaThree Proofs, The Thin Lens Formulas1 Chapter 34 One of the most important uses of the basic laws governing light is the production of images. Images are critical to a variety of fields and industries ranging from entertainment, security, and medicine In this chapter we define and classify images, and then classify several basic ways in which they can be produced. Images34-2The Sun is about 1.5 × 1011 m away. The time for light to travel this distance is about:A. 4.5 × 1018 s B. 8 s C. 8min D. 8 hrE. 8 yr3Image: a reproduction derived from lightReal Image: light rays actually pass through image, really exists in space (or on a screen for example) whether you are looking or notVirtual Image: no light rays actually pass through image. Only appear to be coming from image. Image only exists when rays are traced back to perceived location of sourceTwo Types of Images34-objectlensreal imageobjectmirrorvirtual image4Light travels faster through warm air warmer air has smaller index of refraction than colder air refraction of light near hot surfacesFor observer in car, light appears to be coming from the road top ahead, but is really coming from sky.A Common Mirage34-Fig. 34-15Plane mirror is a flat reflecting surface.Plane Mirrors, Point Object34-Fig. 34-2Fig. 34-3Ib Ob=Identical trianglesPlane Mirror:i p=-Since I is a virtual image i < 06Each point source of light in the extended object is mapped to a point in the imagePlane Mirrors, Extended Object34-Fig. 34-4Fig. 34-57Your eye traces incoming rays straight back, and cannot know that the rays may have actually been reflected many timesPlane Mirrors, Mirror Maze34-Fig. 34-61234567891234567898Plane mirror Concave Mirror1. Center of Curvature C: in front at infinity in front but closer2. Field of view wide smaller3. Image i=p |i|>p 4. Image heightimage height = object height image height > object height 34-Fig. 34-7Plane mirror Convex Mirror1. Center of Curvature C: in front at infinity behind mirror and closer2. Field of view wide larger3. Image i=p |i|<p 4. Image heightimage height = object height image height < object height Spherical Mirrors, Making a Spherical Mirrorconcaveplaneconvex9Spherical Mirrors, Focal Points of Spherical Mirrors34-Fig. 34-8concaveconvexSpherical Mirror:12f r=r > 0 for concave (real focal point)r < 0 for convex (virtual focal point)10Start with rays leaving a point on object, where they intersect, or appear to intersect marks the corresponding point on the image.Images from Spherical Mirrors34-Fig. 34-9Real images form on the side where the object is located (side to which light is going). Virtual images form on the opposite side.Spherical Mirror:1 1 1p i f+ =Lateral Magnification:'hmh=Lateral Magnification:imp=-11Locating Images by Drawing Rays34-Fig. 34-101. A ray parallel to central axis reflects through F2. A ray that reflects from mirror after passing through F, emerges parallel to central axis3. A ray that reflects from mirror after passing through C, returns along itself4. A ray that reflects from mirror after passing through c is reflected symmetrically about the central axis12Proof of the magnification equation34-Fig. 34-10Similar triangles (are angles same) , , (magnification)de cd decd i ca p mab ca abimp= = = =-� =-13Spherical Refracting Surfaces34-Fig. 34-11Real images form on the side of a refracting surface that is opposite the object (side to which light is going). Virtual images form on the same side as the object.Spherical Refracting Surface:1 2 2 1n n n np i r-+ =When object faces a convex refracting surface r is positive. When it faces a concave surface, r is negative. CAUTION: Reverse of of mirror sign convention!1434-Fig. 34-13Converging lensDiverging lensThin Lens:1 1 1f p i= +Thin Lens in air:( )1 21 1 11nf r r� �= - -� �� �Lens only can function if the index of the lens is different than that of its surrounding mediumThin Lenses15Images from Thin Lenses34-Fig. 34-14Real images form on the side of a lens that is opposite the object (side to which light is going). Virtual images form on the same side as the object.16Locating Images of Extended Objects by Drawing Rays34-Fig. 34-151. A ray initially parallel to central axis will pass through F22. A ray that initially passes through F1, will emerge parallel to central axis3. A ray that initially is directed toward the center of the lens will emerge from the lens with no change in its direction (the two sides of the lens at the center are almost parallel)17Two Lens System34-1. Let p1 be the distance of object O from Lens 1. Use equation and/or principle rays to determine the distance to the image of Lens 1, i1.2. Ignore Lens 1, and use I1 as the object O2. If O2 is located beyond Lens 2, then use a negative object distance p1. Determine i2 using the equation and/or principle rays to locate the final image I2.Lens 1Lens 2p1OI1i1O2p2I2i21 2The net magnification is: M m m=18The time for a radar signal to travel to the Moon and back, a one-way distance of about 3.8 × 108 m, is:A. 1.3 s B. 2.5 s C. 8 s D. 8minE. 1 × 106 sRadio waves of wavelength 3 cm have a frequency of:A. 1MHz B. 9MHz C. 100MHz D. 10, 000MHz E. 900MHzThe light intensity 10m from a point source is 1000W/m2. The intensity 100m from the samesource is:A. 1000W/m2B. 100W/m2C. 10W/m2D. 1W/m2E. 0.1W/m219Light of uniform intensity shines perpendicularly on a totally absorbing surface, fully illuminating the surface. If the area of the surface is decreased:A. the radiation pressure increases and the radiation force increasesB. the radiation pressure increases and the radiation force decreasesC. the radiation pressure stays the same and the radiation force increasesD. the radiation pressure stays the same and the radiation force decreasesE. the
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