1. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. The ray model of light Reflection Refraction Dispersion Ray tracing for lenses Ray tracing for mirrors Chapter 18 Ray Optics Topics: Sample question: Why are there two images of this turtle in an aquarium, and why does each image appear to be a different size? Slide 18-1

2. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Reading Quiz 1.When an object like a tree is illuminated by the sun, and you are looking toward the tree, light rays leave the object A.only from points at the top and base of the tree, but in every direction. B.from every point on the surface of the tree, but only toward your eyes. C.only from points at the top and base of the tree, but only toward your eyes D.from every point on the surface of the tree and in every direction. Slide 18-2

3. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. 1.When an object like a tree is illuminated by the sun, and you are looking toward the tree, light rays leave the object D.from every point on the surface of the tree and in every direction. Slide 18-3 Answer

4. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Reading Quiz 2. A light ray can change direction when going from one material into another. This phenomenon is known as A.reflection. B.absorption. C.refraction. D.scattering. Slide 18-4

5. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. 2. A light ray can change direction when going from one material into another. This phenomenon is known as C.refraction. Slide 18-5 Answer

6. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. The Ray Model of Light Light rays travel in straight lines. Light rays can cross. A light ray travels forever unless it interacts with matter. An object is a source of light rays.The eye sees by focusing a bundle of rays. Slide 18-6

7. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Sources of Light Rays: Self-Luminous Objects A ray sourceA point source An extended source A parallel-ray source Slide 18-7

8. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Seeing Objects Seeing a ray source Seeing an object by scattered light Seeing a point or extended source Slide 18-8

9. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Shadows Slide 18-9

10. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. If the aperture is very small, how far apart on the screen built into the left side of the box are the images of the point-like red and green light sources? Example Slide 18-10

11. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. If the aperture is a circle 1 cm in diameter, what are the size and shape of the image of the green point-like light source? Do you need to know how far below the center of the aperture that source is? Example Slide 18-11

12. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. The Law of Reflection Slide 18-12 1.The incident ray and the reflected ray are in the same plane normal to the surface, and 2.The angle of reflection equals the angle of incidence: θ r = θ i.

13. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. The Plane Mirror Slide 18-13

14. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Refraction Slide 18-14

15. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Snell’s Law of Refraction Slide 18-15

16. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-16

17. What is the index of refraction of the plastic if a ray is refracted as in the figure? Example Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-17

18. Total Internal Reflection Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-18

19. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Color and Dispersion Slide 18-19

20. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Thin Lenses and Ray Tracing The focal point of a converging lens The focal point of a diverging lens Slide 18-20

21. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Three Important Sets of Rays: Converging Lenses Slide 18-21

22. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Ray Tracing: Real Images Slide 18-22

23. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-23

24. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Which of these ray diagrams is possibly correct? Checking Understanding Slide 18-24

25. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Which of these ray diagrams is possibly correct? Slide 18-25 Answer

26. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Magnification Slide 18-26

27. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Ray Tracing: Virtual Images Slide 18-27

28. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Three Important Sets of Rays: Converging Lenses Slide 18-28

29. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-29

30. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Checking Understanding In this figure the image is produced by a lens. At which position A–E is the lens? Slide 18-30

31. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. In this figure the image is produced by a lens. At which position A–E is the lens? Slide 18-31 Answer

32. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Spherical Mirrors and Ray Tracing The focal point of a concave mirror The focal point of a convex mirror Slide 18-32

33. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Three Sets of Special Rays for a Concave Mirror Slide 18-33

34. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. A Real Image Formed by a Concave Mirror Slide 18-34

35. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-35

36. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Three Sets of Special Rays for a Convex Mirror Slide 18-36

37. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Ray Tracing for a Convex Mirror Slide 18-37

38. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Slide 18-38