1. HW #5, Due Sep. 28 Exam I: Tuesday Oct. 3 Covers Chapters 1,2,3
Ch. 3: P7, P9, P10, P15, PH5
Reading Assignment For Next Week: Ch.4
REMINDER
Exam I: Tuesday Oct. 3
Covers Chapters 1,2,3

2. Lecture 10 (chapter 3 continued)
Quick Review:
Ray rules for concave mirrors
Finding the image
Lenses
This Lecture:
Ray Rules for Converging and Diverging Lenses
Image Formation
Magnification, etc.

3. Spherical Lenses

4. Refraction at Curved Surfaces
axis O C
center n2 n1
Simply apply the laws of refraction

5. I R
axis O C
center n2 n1

6. Thin Spherical Lenses Converging Lens: focal length (f) is positive
The focal length f depends on curvatures (R1 and R2) and the index of refraction (n) of the material (glass).

7. Thin Spherical Lenses
Converging Lens: focal length (f) is negative

8. Examples of Converging and Diverging Lenses
* Lens Action (Many Applets)
principle rays

9. Ray Rules for Converging (and Diverging) Lenses
Ray Rule 1: All rays incident parallel to the axis are deflected
through F’ (or as if it came from F’)
Ray Rule 2: All rays passing through the center of the lens
Continue undeviated.
Ray Rule 3: All rays that (when extended, if necessary) pass
through F are deflected parallel to the axis.

10. Example: Ray Rules for a converging lens| F’ F | f
f= focal length F’ F |

11. Power of a Lens in diopters in meters * Lens Action (Many Applets)
principle rays

12. Spheres as Thick Lenses
Examples:
Water droplets (dew)
Glass beads ..

13. Dew Heiligenschein: The Holy Light !
Heiligenschein (German for halo) occurs when sunlight falls on nearly spherical dew drops and refracted back toward the sun in the same direction as it enters. It appears as bright white light around the shadow of your head on a dew-covered lawn.

14. Glass Beads as Retroreflectors
Scotchlite

15. Fresnel Lenses

16. Lens Aberrations Chromatic

17. Spherical Aberration

19. *Thick Lens (Spherical Aberration)

20. Curvature, Coma

21. Astigmatism

22. Distortion

23. NEXT: CHAPTER 4 *Thick Lens (Spherical Aberration)
NEXT: CHAPTER 4
*Magnification (Magnifying Glass)