2. Warm-up: The index of refraction for acetone is 1. 36
Warm-up: The index of refraction for acetone is What is the speed of light in acetone? Vacetone = ?

3. Total Internal Reflection

4. Describe the relationship between the refraction index of a medium and the speed of light passing through that medium. As the index of refraction increases, the speed of light slows down. For example, light moves slower in acrylic than quartz.
Medium n
Vacuum/space and Air
1.00
Ice
1.31
Water (pure)
1.33
Ethyl alcohol
1.36
Quartz
1.46
Vegetable oil
1.47
Olive oil
1.48
Acrylic
1.49
Glass
1.52
Diamond
2.42

5. Draw and label a ray diagram of light moving from water to air.

6. Light bends away from the normal when it speeds up at the boundary of two medium, (ie from water to air). In this situation the angle of refraction is larger than the angle of incidence.
Critical angle
Eventually the angle of refraction will increase so it is 90o.
The angle of incidence that produces an angle of refraction of 90o is the critical angle.

7. Total internal reflection
If you increase the angle of incidence PAST the critical angle, the refracted ray will no longer exit the medium. Instead it will reflect back into the medium. The refracted ray will disappear and only a reflected ray is visible.
Total internal reflection: When the angle of incidence is greater than the critical angle

8. When light travels from slower to faster medium….
Option 1:
-Incident angle < critical angle
-Ray is refracted into air
Option 3:
-Incident angle > critical angle
-Ray reflected internally
Option 2:
-Incident angle = critical angle
-Ray refracted at 90o

9. Draw a ray diagram of light as it moves through a diamond
Diamonds are cut to take advantage of their critical angle of A properly cut diamond will sparkle more because the light reflects out the top of the diamond.

10. Review… Fiber optic Cables: How they work https://www. youtube
Review… Fiber optic Cables: How they work Making fiber optic wire

11. Practice: Complete rest of worksheet -Questions 1, 2, 8 Wednesday: QUIZ! 1) Images in plane mirrors 2) Images in convex and concave mirrors 3) Index of refraction and speed of light