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$Math Alignment Project - Grand Erie District School First Class Web ...$

SCIENCEeverywhereSelf-AdjustingGlassesThe man in this photograph iswearing glasses that correct hisblurry vision. The unusual thingis that he adjusted his ownlenses without the help of anoptometrist in determining hislens prescription. In fact, overone billion people in the worlddo not have access to anoptometrist. Low-cost glassesthat can be adjusted by thewearer may be part of thesolution for making good quality,low-cost vision correction areality for the whole world.This pair of self-adjusting glasses is constructed by sandwiching a fluid-filled sacinside a flexible plastic lens. More fluid means a thicker lens and a strongercorrection in the glasses. To make an adjustment, the wearer uses a small syringeto add or remove the fluid, and a small screw to lock the amount of fluid in thelens. One design hurdle is finding a way to produce the glasses in bulk cheaply.Another difficulty is the bulky frame that is currently needed. Dr. Silver and othersare working to overcome these difficulties.The inventor of self-adjusting glasses isJoshua Silver, a professor at Oxford Universityin England. Dr. Silver wondered whetherpeople could correct their own vision if theycould manually adjust the focussing power ofthe lenses. This would be just like anyonefocussing a camera or a pair of binoculars. By2008, Dr. Silver had already seen 30 000pairs of his self-adjusting glasses delivered topeople in 15 developing countries. By 2020,he would like to see 100 000 pairs distributedannually at a cost of less than $2 per wearer.Ray diagrams model the behaviour of light in mirrors and lenses.463
11 CHAPTER REVIEWACHIEVEMENT CHART CATEGORIESk Knowledge and understandingc CommunicationKey Concept Reviewt Thinking and investigationa Application1. Describe how the law of reflection appliessimilarly to regular and diffuse reflection.2. Use a ray diagram to show why imagesproduced by plane mirrors are considered tobe virtual images. k3. (a) Name three places where concave mirrorsare useful. k(b) Name three places where convex mirrorsare useful. k4. (a) What are the properties of images that aconvex mirror can produce? k(b) What are the properties of images that aconcave mirror can produce? k5. (a) What are the properties of images that aconcave lens can produce? k(b) What are the properties of images that aconvex lens can produce? k6. Explain why the speed of light can vary whenit travels through transparent or translucentmaterials. t7. Explain what happens to the direction of alight ray if it enters a medium with a lowerrefractive index. k8. Explain why the incident and refracted anglesare measured from the normal instead of thesurface. kk11. Draw ray diagrams for a diverging mirror andstate the characteristics of the image at thefollowing object positions: k(a) 1.0 f (b) 0.50 fConnect Your Understanding12. A convex lens is placed near an object. Theheight of the image is 3.8 mm, giving amagnification of 0.26.(a) What is the height of the object? a(b) Does the answer depend on whether theimage is real or virtual? Explain. t13. Describe the properties of a lens thatdetermine its focal length. t14. The image of a 30-cm-tall rose is captured bya camera with a 28-mm lens. The imageforms 29 mm behind the lens.(a) How far is the lens from the rose? a(b) How high is the image? a15. Light passes from a diamond into air. Theangle of refraction as the light emerges fromthe diamond is 25°. What was the angle ofincidence? a16. A ray of light passes from the air into asapphire at an incident angle of 15°.Calculate the angle of refraction. a17. An eyelash mite measures 0.28 mm long.What is the magnification if a microscopeproduces a 56-mm image? a9. What properties of light does Snell’s lawexplain? k10. Draw ray diagrams for a converging mirrorand state the properties of the image formedfor the following object positions: k(a) 3.0 f (b) 1.4 f (c) 0.70 fQuestion 17464 UNIT D
Page 1 and 2: 11Ray diagrams model the behaviour
Page 3: 11.1MirrorsHere is a summary of wha
Page 6 and 7: Using the Law of ReflectionThe law
Page 8 and 9: Concave MirrorsA concave mirror, al
Page 10 and 11: Solar OvensA solar oven, also calle
Page 12 and 13: Example Problem 11.3An electron mic
Page 14 and 15: Uses for Convex MirrorsIf you were
Page 16 and 17: D14 Skill Builder ActivityDrawing R
Page 18 and 19: D15 Inquiry Activity (continued)Fig
Page 20 and 21: 11.1 CHECK and REFLECTKey Concept R
Page 22 and 23: We use fibre optics systems to tran
Page 24 and 25: A ray of light is electromagnetic r
Page 26 and 27: How Light RefractsYou can picture t
Page 28 and 29: Snell’s LawThe phenomenon of refr
Page 30 and 31: At a certain angle, called the crit
Page 32 and 33: D19 Inquiry ActivityIndex of Refrac
Page 34 and 35: 11.2 CHECK and REFLECTKey Concept R
Page 36 and 37: Night vision goggles use lenses to
Page 38 and 39: Concave LensesA diverging lens is s
Page 40 and 41: Forming a Real ImageConvex lenses a
Page 42 and 43: Keep in mind the following points w
Page 44 and 45: Example Problem 11.11A camera with
Page 46 and 47: D24 Quick LabFocal LengthPurposeTo
Page 48 and 49: D26 Inquiry ActivityIdentifying the
Page 52: 18. A student looks at the letters

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