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

At a certain angle, called the critical angle, the refracted ray of lightfollows a path exactly along the surface of the water. Even though thelight refracts, it does not leave the water. In a way, the light is “trapped”inside the water (Figure 11.40).0°20°27°30°42°40°59°90°60° 60°air n 1.00water n 1.33Take It FurtherRefractive index has many uses,including identifying gemstones.It can also be used to find theconcentration of solutions. Findout about these and other uses ofthe refractive index. Begin yourresearch at ScienceSource.0°critical angle 48.8°light sourceFigure 11.40 When theangle of incidence is greaterthan the critical angle, totalinternal reflection occurs.What if the angle of the incident ray is increased even farther? Thelight ray is no longer refracted. Instead, it is completely reflected backinside the water. In an optical fibre, light is passed into the end of thefibre at an angle greater than the critical angle. Because the fibre is madeof glass, which has a higher index of refraction than the surroundingmedium, the light ray is completely reflected inside the fibre.Suggested Activity •D20 Design a Lab on page 446MiragesBoth total internal reflection and refraction play a role in forming amirage (Figure 11.41). A mirage is an image of a distant objectproduced as light refracts through air of different densities(Figure 11.42). Since the light rays pass through layers of air withprogressively lower indices of refraction, eventually the light is totallyinternally reflected.light rayfrom skylight rayfrom cloudobservercloudless dense, hot airmore dense, cool airhot pavementFigure 11.41 What looks like apuddle of water from the distance isactually an image of the sky that isproduced as light from the sky is bentnear the surface of the road up intothe eyes of the observer.image of cloudFigure 11.42 Light from an object in the sky is refracted due to the difference in density of theair above the pavement compared with the air higher up.Ray diagrams model the behaviour of light in mirrors and lenses.443
D18 Inquiry ActivityRefraction Measurement and PatternsSkills References 2, 8SKILLS YOU WILL USE■ Interpreting data/information toidentify patterns or relationships■ Identifying sources of errorQuestionWhat is the refractive index of tap water?Materials & Equipment• adhesive tape• 360° protractor• an aquarium ortransparent containerwith flat vertical sides• water• ray box with single slit• scientific calculatorCAUTION: Do not shine bright light into anyone’s eyes.Incandescent light sources can become very hot. Do nottouch the bulbs or block air flow around the light bulbs.3. Fill the container with water so that the protractoris completely below the water line (Figure 11.43).The 90° angle is the normal for the incoming ray.The 270° angle is the normal for the water.4. Hold the ray box so that the beam of light traces apath across the face of the protractor and entersthe water. Begin with the angle 5° above thenormal. This should be the 95° angle on theprotractor. Record the refracted angle of the beamin water. Remember to measure magnitude of thisangle from the 270° mark on the protractor.5. Repeat step 4 for increments of 5° up to 50°.6. Calculate sinθ 1 and sinθ 2 for each measuredvalue of θ 1 .7. Draw a scatter plot of sinθ 2 against sinθ 1 .Analyzing and Interpreting8. Is there a pattern in the data? Explain.9. (a) Find the slope of the line.(b) Using Snell’s law as a guide, determine whatthe slope represents.(Hint: what doessinθ 1sinθ 2equal?)Figure 11.43 Step 3Procedure1. Make a table with the following headings. Giveyour table a title.θ 1θ 2sinθ 1sinθ 22. Tape the protractor to the container near thebottom so that the line from 0° to 180° is alignedvertically with the container’s edge. Half theprotractor should be flush with the side of thecontainer, and the other half should be in air.10. Assume the index of refraction of air is 1. Use theslope of the line to determine the index ofrefraction of water.Skill Practice11. The closer the points are to a straight line, thebetter your measurement skills. What does yourgraph suggest about the quality of your datacollection skills?12. Why should a scatter plot of θ 2 against θ 1 not becompletely straight?Forming Conclusions13. Look up the index of refraction of water inTable 11.5 on page 437. How close was yourvalue to this value? Explain any difference.444 UNIT D Light and Geometric Optics
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 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 50 and 51: SCIENCEeverywhereSelf-AdjustingGlas
Page 52: 18. A student looks at the letters

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