1. Light Spectrum

2. Remember when we said that light travels as electromagnetic waves? Well, what is an electromagnetic wave? EM wave: coupled, changing electric and magnetic field that travels through space EM radiation: energy that is carried, or radiated, in the form of EM waves EM spectrum: the entire range of frequencies and wavelengths that make up all forms of EM radiation –Ex: radio waves, microwaves, visible waves, and x-rays

3. The Electromagnetic Spectrum

4. The EMS are transverse waves that carry both magnetic and electric energy. Each type of EMW is defined by its wavelength. Wavelengths range from 104 m (10,000 m) to 10-15 m (0.00000000000001 m).

5. Radio/TV Waves Radio waves come in three types: Frequency modulation (FM), amplitude modulation (AM), and then there are the lowest frequencies, which are used by two way radios, etc.

6. Radio Waves and Electromagnetic Fields Simulation

7. Visible Light The part of the spectrum that we can see is called visible light. It is the smallest portion of the spectrum.

8. c = speed of light in a vacuum = 2.9979 x 10 8 m/s = 3.0 x 10 8 m/s

9. v = f c = f

10. White Light and Color

11. Newton’s Light Experiment So, Newton figured out that white light is composite (made up of other colors)…but how did he do it?

12. Not just one prism…

13. But TWO!

14. Each color in the spectrum is associated with a wavelength

15. PRIMARY COLORS The colors, that when added together, form white light (Red, Blue, Green)

16. ADDITIVE COLOR PROCESS red + blue + green = white

17. SECONDARY COLORS The colors, that are formed when two primary colors are added together (yellow, cyan, magenta)

18. SECONDARY COLORS

20. What does it really mean to see color?

21. Ray Model

22. Reflection from Smooth and Rough Surfaces

23. Reflection

24. Problem

25. Refraction

26. An Analogy for Refraction

27. The Basic Mechanism of Refraction

28. SNELL’S LAW

30. Indices of Refraction

31. Example in notes… r n1  sin  A beam of light of wavelength 550 nm traveling in air is incident on a slab of transparent material. The incident beam makes an angle of 40.0  with the normal, and the refracted beam makes an angle of 26.0  with the normal. Find the index of refraction of the material.

32. Refraction Summary If there is no change in index of refraction the light is not deflected. As light goes from a low n to a high n it is bent toward the normal. The greater the difference the greater the deflection. As light goes from a high n to a low n it is bent away from the normal. The greater the difference the greater the deflection. If the light is incident on the surface of the material along a normal path, there is no deflection.

33. Dispersion

34. Index of Refraction Revisited

35. Dispersion in a Raindrop

36. Figure 26-38 How Rainbows Are Produced

37. Total Internal Reflection

38. Critical Angle Equation sinθ c =n 2 /n 1 Try the one in your notes…

39. How We See Objects P P P′P′

40. Locating a Mirror Image

41. Spherical Mirrors

42. Concave and Convex Mirrors

43. Real vs. Virtual Real images are formed by converging light rays. Virtual images are formed by diverging light rays.

44. Principal Rays Used in Ray Tracing for a Concave Mirror

45. Image Formation with a Concave Mirror

46. Inside the Focal Point

47. Principal Rays Used in Ray Tracing for a Convex Mirror

48. Image Formation with a Convex Mirror

49. Refraction and the “Bent” Pencil

50. How is the ray deflected?

51. Comparing Lenses with a Pair of Prisms

52. Lenses Converging LensesDiverging Lenses Convex Meniscus PlanoconvexDoubleconvex Concave Meniscus PlanoconcaveDoubleconcave

53. The Three Principal Rays Used for Ray Tracing with Convex Lenses

54. Rules for lens diagrams Converging lenses 1.P ray starts parallel then heads toward focal point 2.F ray starts from or heads toward focal point then goes parallel 3.M ray goes straight through the middle

55. F F Where’s The Image?

56. F F

57. Diverging lenses 1.P ray starts parallel then heads away from focal point 2.F ray starts from or heads toward far focal point then goes parallel 3.M ray goes straight through the middle

58. The Three Principal Rays Used for Ray Tracing with Concave Lenses

59. Where’s The Image? F F

60. Describe the Image F F

61. Two Lenses

62. Thin Lens Equation