1. HW #3, Due Sep. 14
Chapter 2
P23, P24, PH13, PH15, PM2

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3. Lecture 6 (chapter 2 continued)
Quick Review:
Reflection and mirrors
Sub Sun and Sun Pillars
Multiple Reflection
This Lecture:
Refraction
Total Internal Reflection
Refraction in Nature (Mirages, Halos, Rainbows,..)

4. Reflectivity (how much is reflected?)
Grazing Incidence Reflection (glass windows, water surfaces, waxed floors, etc.)

5. Who sees me in the mirror?!
image
(field of view)
Simply apply law of reflection and trace the rays…

6. Sun Pillars and Sub Suns

7. Ice Crystals

8. Sub Sun

10. Sun Pillar

11. Multiple Reflections Example: Second Surface Mirrors

12. Corner Reflectors
Retroreflectors

13. Refraction Recall: velocity of light v= c/n

15. *Refraction 1
Fish Tank

16. Material Refractive Index (n) Air 1.0003
Examples
Material Refractive Index (n)
Air
Water
Glycerin
Immersion Oil
Glass 1.52
Flint
Zircon
Diamond
Silicon 4

17. Law of Refraction N i I Air (for example) n1 glass or water or … n2 R
The Refracted ray (R ) lies in the plane defined by Incidence ray (I) and surface Normal (N)
The Refracted ray (R ) lies on the opposite side of N as the incident ray I, and
The Refracted ray (R ) makes an angle r that satisfies the Snell’s law:
Angle of Incidence  Index of refraction in medium 1 almost equals to Angle of Refraction  Index of refraction in medium 2
(for small angles)

18. Snell’s Law (exact) c a 
Sine of an angle

19. Now, consider this ….

20. Total Internal Reflection
*Total Internal Reflection (Optical Fiber)

21. Total Internal Reflection

22. Prisms as perfect reflectors:
See Fig in the Text

23. Brilliance (TIR), Fire (dispersion) and Flash
Diamond
Brilliance (TIR), Fire (dispersion) and Flash

24. Mirages, Rainbows, Halos, Sun Dogs….
Next
Refraction in Nature
Mirages, Rainbows, Halos, Sun Dogs….

25. Mirages and Atmospheric Distortions
sunset
mirage

26. Mirage

27. Dispersion Refractive Index varies with Wavelength : n()
Dispersion in a prism
* Prism Refraction
refraction & refl.
dispersion

29. Rainbow

30. Rainbow *Rainbow http://www.phy.ntnu.edu.tw/java/Rainbow/rainbow.html
rain drop

33. Ice Crystals

34. Sun Dogs

39. Halos

41. 22 degree halo

42. 22 degree halo

43. 46 degree halos

44. Reflection in Curved Mirrors
Chapter 3
Reflection in Curved Mirrors

45. Mirrors
*Concave Mirrors
*Concave Lens: virtual image
*Convex Mirrors
spherical aberration