1. Refraction and Reflection
Chapter 28
Refraction and Reflection

2. Reflection i r 1. Angle of incidence (i) = Angle of reflection (r)
2. Incident ray, normal, and reflected ray coplanar

3. Diffuse Reflection
If successive elevations of a surface are no more than l/8 apart, then the surface is said to be polished at that wavelength.
Most objects are seen by diffuse reflection.

4. Ray Diagramming
Plane Mirror

5. Plane Mirrors
Object
Image

6. Plane Mirrors
Image Properties:
Virtual
Erect
Same Size

7. Reflection from Curved Surfaces (Concave shown here)
Ray Diagramming f
Principal axis
Reflecting Surface
The law of specular reflection is still obeyed.

8. Fermat’s Principle
Light travels in straight lines and takes the path of least time.
Predicts both reflection and refraction

9. Beach
Water
Whoa
Baby
Help
Help
Help

10. Refraction i
air ni
water nR R

11. Index of Refraction speed of light in vacuum n =
speed of light through medium
n = c / v ³ 1
ni sin qi = nR sin qR
Snell’s Law

13. Because of atmospheric refraction,
we have lingering, elliptical sunsets.
Sun
Earth
Sun

14. Sunset

15. Mirage
Cool air
Warm air
Surface of water?

16. Looming
Warm air
Cool air

17. 960

18. Total Internal Reflection
Critical Angle

19. Two Prisms in a Monocular

20. Dispersion in a Prism

21. Mercury Near Horizon

22. Rainbows

23. Green Flash Sun Earth Dispersion occurs causing
multiple images of the sun.
The last to set would be blue,
but most of the blue has been
scattered which leaves green.

24. Green Flash

25. Lenses
Converging Lens

26. Lenses
Diverging Lens

27. Ray Diagramming f
Principal axis
Applet1

28. Various Lenses Convex lenses are positive converging lenses.
Double
Convex
Double
Concave
Plano
Convex
Plano
Concave
Convex
Meniscus
Concave
Meniscus
Convex lenses are positive converging lenses.
Concave lenses are negative diverging lenses.

29. Lens Defects
white
Chromatic Aberration
Spherical Aberration

30. Pinhole