1. Reflection vs. Refraction

2. Refraction Refraction of Light: Bend or change direction
1. As light rays enter a new medium the cause light to bend
2. The denser the medium – the slower the light travels
3. Index of Refraction: a measure of how much a medium bends the light that travels through it.
4. The faster the beam, it will bend away from normal, the slower the beam, it will bend toward the normal.

3. A mirage is a visual distortion produced by the refraction of light.
Some mirages produce a mirror or a watery image, and others may make an object appear larger or smaller, nearer or further away.

5. The ray model says…
Light has four different ways in which it can interact with matter.
Medium 1
Medium 2
Reflection

6. Light has four different ways in which it can interact with matter.
Medium 1
Medium 2
Refraction

7. Light has four different ways in which it can interact with matter.
Medium 1
Medium 2
Scattering

8. Light has four different ways in which it can interact with matter.
Medium 1
Medium 2
Absorption

9. Reflective Objects

10. Reflection Diffuse Reflection Regular Reflection Reflection off Paper
Reflection off a Mirror

11. Law of Reflection
Normal - an imaginary line drawn perpendicular to the surface

12. Reflections in a Mirror

13. Q

14. An observer observes a light source S in a mirror
An observer observes a light source S in a mirror. Where does he perceive the mirror image of S to be located? ●1 ●3 ●4 S ●2

15. How big does a mirror have to be in order to see your entire length in it?
Half His Height!

16. To see more of her head in the mirror, she …
1. should hold the mirror closer
2. should hold the mirror farther away
3. needs a bigger mirror

18. Refraction

19. Refraction
As light travels from one medium to another, the speed of light changes and the light bends accordingly. i R

20. n1 sin I = n2 sinR Snell’s Law: The Law of Refraction
Index of Refraction of the media in which the angle of incidence is
Index of Refraction of the media in which the angle of refraction is

21. Index of Refraction Cannot be less than 1.00 Air = 1.00 Glass = 1.5
Water = 1.33

22. Q

24. Bruno wishes to “spear” a fish with a laser
Bruno wishes to “spear” a fish with a laser. Should he aim the laser beam…
above below directly at
the observed fish to make a direct hit?

26. Light is incident on a block of glass as shown
Light is incident on a block of glass as shown. Which ray is the refracted ray? 1. 2. 3. 4.

27. Calculate the critical angle θ from glass (n=1.5) to air.
52.9o o o
o o θ

28. Calculate the critical angle θ from glass (n=1.5) to air.
52.9o o o
o o θ
n1 sin I = n2 sinR
1.5 sin I = 1.0 sin 90
sin I = .667
I = 41.8

29. Fiber Optics

30. Fiber optics uses total internal reflection