1. Geometrical Optics Chapter 24 1

2. This week  This week we begin the study of optics. I have no idea how far we will get into these chapters.  Lenses & Mirrors  Interference  Diffraction  Probably not enough material to justify a 7:00AM class. We can use office hours for that purpose.  There will be a quiz on Friday.  Watch for a new Mastering Physics (I know you just can’t wait!)  Last quiz is in the bin. 2

3. From the website: Remaining Clicker Evil Fix this evil or you will have a ZERO clicker score!! Practice Problem Set (Monday Session) ****** TAKE NOTE OF THE FOLLOWING ****** The end of the semester is approaching. The common Final Examination will be on Saturday, Dec 12, 2009 from 9AM-12PM in room PSY 108 There will be one more exam this semester but it probably will be on December 2 (Wednesday). This exam will cover the remaining material covered. It will also be covered in the final exam. Don't forget to check the evil clicker file! 3

4. Geometrical Optics Yup … more angle stuff! 4

5. Geometrical Process Lens or Mirror Object Image Oh where, oh where, has my bug’s image gone.. oh where or where can it be??? 5

6. Where’s the image, where’s the object … who cares??? We do!  What kind of an image is it?  Real  Virtual  Where is the object, where is the image?  Behind the lens  In front of the lens  Where is the light coming from? Where is it going?  What is the size of the image? (magnification)  What is the orientation of the image?  Same as the object,  Inverted (upside down)  Reverse Questions about the image: 6

7. What kind of optics:  Mirror  Planar  Concave  Convex  Lens  converging  diverging  Where is the light?  Have you seen the light yet? 7

8. Note  The object is usually the source of light.  The image is where the light converges to replicate the object.  The image can be on either side of the “optical element”  The image can be real or virtual  The image can form an object for a second optical element.  Yes.. it can be confusing. We will attack this a point at a time. 8

9. Signs 9

10. Signs – We mean (-) or (+)  The distance from the object to the lens/mirror is called the object distance.  It is positive if it is on the same side of the optical element as the incoming light. Otherwise it is negative  It is designated by s  The distance from the image to the lens/mirror is called the image distance.  It is positive if it is on the same side as the outgoing light  It is designated by s’. Otherwise it is negative.  Without this sign convention, these problems would be much more difficult. So pay attention to them!! 10

11. 11

12. 12

13. Paraxial Rays : Small Angle Approximation thetasintan 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.23 0.24 0.25 0.26 0.27 0.28 0.29 0.30 0.31 13

14. 14

15. 15

16. Curved Mirrors For Student Misery Only! 16

17. Concave Mirror con-CAVE 17

18. Sign Convention When the Center of Curvature is on the same side of the outgoing ray, R is positive. Otherwise, if the center of curvature is not on the same side as the outgoing ray, R is negative. 18

19. Concave Mirror/Paraxial Approximation The normal to the surface passes through C Therefore Consequently MIRROR EQUATION 19

20. For this structure A. The Radius R is positive and s’ is negative B. The Radius R is negative and s’ is negative C. R is positive and s’ is positive D. R is negative and s’ is positive Answer 20

21. When the Center of Curvature is on the same side of the outgoing ray, R is positive. the image distance is positive if it is on the same side as the outgoing light 21

22. What about here? R, s, s’ (convex mirror) 22

23. Concept: Focal Length of a Mirror 23

24. Going Backwards 24

25. More Better – A Parabola 25 surveillance

26. Image Formation 26 ‘ ‘ y’<0 (from the diagram) so image is inverted.

27. The geometry…… 27

28. A concave spherical mirror has a radius of 10 cm. Calculate the location and size of an 8mm object a distance 15 cm from the mirror. 28 10 cm 5 cm Normal to mirror and bounces back along incoming path.

29. A concave spherical mirror has a radius of 10 cm. Calculate the location and size of an 8mm object a distance 10 cm from the mirror. 29 10 cm 5 cm

30. A concave spherical mirror has a radius of 10 cm. Calculate the location and size of an 8mm object a distance 2.5 cm from the mirror. 30 10 cm 5 cm eye virtual image