1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Refraction Chapter 14 Refraction of Light The speed of light in a vacuum, c, is 3.00 x 10 8 m/s. Inside of other mediums, such as air, glass, or water, the speed of light is different and is slightly less than c. As a light ray travels from one medium into another medium where its speed is different, the light ray will change its direction unless it travels along the normal. The bending of light as it travels from one medium to another is call refraction.

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Refraction Section 1 Refraction

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Wave Model of Refraction Section 1 Refraction

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Refraction Chapter 14 The Law of Refraction The index of refraction for a substance is the ratio of the speed of light in a vacuum to the speed of light in that substance.

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Indices of Refraction for Various Substances Section 1 Refraction

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Refraction Chapter 14 The Law of Refraction, continued When light passes from a medium with a smaller index of refraction to one with a larger index of refraction (like from air to glass), the ray bends toward the normal. When light passes from a medium with a larger index of refraction to one with a smaller index of refraction (like from glass to air), the ray bends away from the normal.

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Refraction Section 1 Refraction

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Refraction Chapter 14 The Law of Refraction, continued Objects appear to be in different positions due to refraction.

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Refraction Chapter 14 The Law of Refraction, continued Snell’s Law determines the angle of refraction.

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Image Position for Objects in Different Media Section 1 Refraction

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Practice A Pg. 493 # 1, 3

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Practice Problems 1.H. G. Wells wrote a famous novel about a man who made himself invisible by changing his index of refraction. What would his index of refraction have to be to accomplish this? 2.Would the invisible man be able to see anything? 3.Find the angle of refraction for a ray of light that enters a bucket of water from the air at an angle of 25.0° to the normal. 4.Open books to page 493 and finish number 2 Chapter 14 Section 1 Refraction

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lenses A transparent object that refracts light rays such that they converge or diverge to create an image. Examples: Human eye Eye glasses Camera Microscope Telescope Reading stones used by monks, nuns, and scholars ~1000 C.E.

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lenses THERE ARE ALWAYS TWO REFRACTIONS IN A LENS

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Lenses Two basic shapes Converging (convex) lens Diverging (concave) lens

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Focal Length for Converging and Diverging Lenses Section 2 Thin Lenses

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Converging Lens A lens that has its thickest part in the middle Causes all incident parallel rays to converge at a single point (the focal point) after refraction

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Converging Lens OPTICAL CENTER: the exact center of the lens

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray diagrams for Converging Lenses

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray diagrams for Converging Lenses

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Images through Converging Lenses Let’s practice

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Converging Lenses Can produce real and virtual images The size and attitude will vary depending on the location of the object Many uses including to correct for far-sightedness LocationSizeAttitudeLocationType Beyond 2F ’ SmallerInvertedBehindReal At 2F ’ SameInvertedBehindReal Between 2F ’ and F ’ LargerinvertedBehindReal At F ’ No clear image Inside F ’ largeruprightIn frontVirtual Object Image -------------------------------

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diverging Lens A lens that has its thinnest part in the middle Causes all incident parallel light rays to spread apart after refraction

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diverging Lens

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray diagrams for Diverging Lenses

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Ray diagrams for Diverging Lenses

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Images through Diverging Lenses Let’s practice

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Diverging Lenses Only produce virtual images that are always smaller, upright and in front of the lens Used to correct near-sightedness (can see objects close up)

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Thin Lenses Chapter 14 The Thin-Lens Equation and Magnification The equation that relates object and image distances for a lens is call the thin-lens equation. It is derived using the assumption that the lens is very thin.

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Thin Lenses Chapter 14 The Thin-Lens Equation and Magnification, continued Magnification of a lens depends on object and image distances.

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu + object distance - Image distance + focus +Image distance Converging lens: Diverging lens: + object distance - Image distance - focal length

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Practice B An object is placed 30.0 cm in front of a converging lens with a focal length of 10.0 cm. Find the image distance and the magnification. Same object is placed 12.5 cm in front of a diverging lens with focal length of 10.0 cm. Find the image distance and the magnification. Pg. 501 #1, 2, 3

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Applications of Lenses

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Thin Lenses Chapter 14 Eyeglasses and Contact Lenses The transparent front of the eye, called the cornea, acts like a lens. The eye also contains a crystalline lens, that further refracts light toward the light-sensitive back of the eye, called the retina. Two conditions, myopia and hyperopia, occur when light is not focused properly retina. Converging and diverging lenses can be used to correct these conditions.

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Section 2 Thin Lenses Farsighted and Nearsighted

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Thin Lenses Chapter 14 Combination of Thin Lenses An image formed by a lens can be used as the object for a second lens. Compound microscopes use two converging lenses. Greater magnification can be achieved by combining two or more lenses. Refracting telescopes also use two converging lenses.

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Compound Light Microscope Section 2 Thin Lenses

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Refracting Telescope Section 2 Thin Lenses

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Total Internal Reflection Total internal reflection can occur when light moves from a medium with a higher index of refraction to one with a lower index of refraction. At the critical angle, refracted light makes an angle of 90º with the normal. Above the critical angle, total internal reflection occurs and light is completely reflected within a substance.

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Total Internal Reflection

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Optical Phenomena Chapter 14 Total Internal Reflection Total internal reflection can occur when light moves along a path from a medium with a higher index of refraction to one with a lower index of refraction. At the critical angle, refracted light makes an angle of 90º with the normal. Above the critical angle, total internal reflection occurs and light is completely reflected within a substance.

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Optical Phenomena Chapter 14 Total Internal Reflection, continued Snell’s law can be used to find the critical angle. Angle of incidence is the critical angle and angle of refraction is 90 degrees. Total internal reflection occurs only if the index of refraction of the first medium is greater than the index of refraction of the second medium.

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Total Internal Reflection Section 3 Optical Phenomena

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Optical Phenomena Chapter 14 Atmospheric Refraction Refracted light can create a mirage. A mirage is produced by the bending of light rays in the atmosphere where there are large temperature differences between the ground and the air.

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Dispersion of Light Section 3 Optical Phenomena

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 Optical Phenomena Chapter 14 Dispersion Dispersion is the process of separating polychromatic light into its component wavelengths. White light passed through a prism produces a visible spectrum through dispersion.

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Section 3 Optical Phenomena Rainbows

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chromatic Aberration When all colors of light do not come to focus at the same point Because of dispersion (prisms, rainbows), violet light refracts more than red light

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu

51. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Correction Spherical & chromatic aberrations can be “corrected” High quality lenses for expensive cameras use a combination of many lenses to reduce aberration as much as possible

52. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Converging and Diverging Lenses Section 2 Thin Lenses

53. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Ray Tracing for a Converging Lens Section 2 Thin Lenses

54. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Chapter 14 Ray Tracing for a Diverging Lens Section 2 Thin Lenses