2. Ch 15.1 - Refraction

3. Definition: Refraction Change in speed of light as it moves from one medium to another. Can cause bending of the light at the interface between media.

4. Index of Refraction The ratio of the speed of light in a vacuum to its speed in a given transparent medium

5. Index of Refraction speed of light in vacuum speed of light in medium n = c/v n =

6. Snell’s Law n1n1 n2n2 11 angle of incidence 22 angle of refraction n 1 sin  1 = n 2 sin  2

7. n 1 < n 2 n1n1 n2n2 11 22 light bends toward normal

8. n 1 > n 2 n1n1 n2n2 11 22 light bends away from normal

9. Homework P567 #1-3 (Snell’s Law) P567 #1-3 (Section Review)

10. 15.3 – Optical Phenomena

11. Dispersion Dispersion The separation of white light into colors due to different refractive indices for different wavelengths.

12. Dispersion Dispersion Due to different indices of refraction for different wavelengths of light.

13. Useful Definitions Total Internal Reflection – the complete reflection of light at the boundary of two transparent media Critical Angle – the minimum angle of incidence for which total internal reflection occurs

14. Critical Angle of Incidence n1n1 n2n2 cc Light would refract 90 o so it reflects instead, undergoing total internal reflection. rr n 1 > n 2

15. Calculating Critical Angle Calculating Critical Angle n 1 sin(  1 ) = n 2 sin(  2 ) n 1 sin(  1 ) = n 2 sin(90 o ) n 2 = n 1 sin(  c )

16. Total Internal Reflection n1n1 n2n2 i r Occurs only when angle of incidence > critical angle

17. Homework P582 #1-4, p585 #1-3

18. 15.2 – Thin lenses

19. Lens types Converging – can produce real or virtual images Diverging – can produce only virtual images

20. Ray diagrams Same rays as we drew for mirrors Rays will always go through the mirror (not reflected) but will be somehow bent (refracted)

21. Useful Definitions Lens – a transparent object that refracts light rays, causing them to converge or diverge to create an image. **Big difference with mirrors** –Real is on the right side of the lens. Why? + side of mirror is ride side - side of mirror is left side

22. Converging lens #1 CF Real, Inverted, Reduced Image F2F

23. Converging lens #2 CF Real, Inverted, True (Same size) Image F2F

24. Converging lens #3 CF Real, Inverted, Enlarged Image F2F

25. Converging lens #4 CF Virtual, Upright, Enlarged Image F

26. For converging lenses f is positive p is positive q is positive for real images and negative for virtual images M is negative for real images and positive for virtual images h i is negative for real images and positive for virtual images

27. Diverging lens CF Virtual, Upright, Reduced Image F

28. For diverging lenses f is negative p is positive q is negative M is positive and < 1 h i is positive and < h o

29. Homework P576 #1-4