1. Journal #81 April 22, 2011 Use the concave and convex mirrors on your table. Start with the mirror very close to your eye and slowly back it away. Describe the changes to your image until the mirror is a full arm’s length away You do not need to copy this paragraph

2. Answer to Journal #81 Concave: The image starts off very close to regular size and increases in size. Image becomes completely blurred. Image reforms and is inverted and enlarged. It becomes reduced the farther away you move beyond this point. Convex: The image starts off very close to regular size but reduces as the mirror is pushed back. Also, image is not a true representation of object… slightly skewed.

3. Plane Mirror Reflection is on top of incident light Image formed is: Virtual Upright Same Size Image formed is: Virtual Upright Same Size

4. Try to fill in this chart from memory… best way to study! Object Placement/Mirror Real or Virtual Upright or Inverted Size of image compared to size of object Plane Mirror B/n Concave Mirror and FP At FP of Concave Mirror B/n FP and CC of Concave Mirror At CC of Concave Mirror Beyond CC of Concave Mirror Convex Mirror

5. Answer Key to Table Object Placement/Mirror Real or VirtualUpright or Inverted Size of image compared to size of object Plane MirrorVirtualUprightSame B/n Concave Mirror and FP VirtualUprightEnlarged At FP of Concave Mirror No Image B/n FP and CC of Concave Mirror RealInvertedEnlarged At CC of Concave Mirror RealInvertedSame Beyond CC of Concave Mirror RealInvertedReduced Convex MirrorVirtualUprightReduced

6. How to make a study game Take 4 sheets of blank paper and fold them in half 3 times to create 8 equal sized sections Cut each of the rectangular shapes made by the creases

7. How to make a study game Lay out the individual rectangles in a 4 by 8 grid

8. How to make a study game Remove the bottom row and save them as extras (in case you make a mistake)

9. How to make a study game In the first column, write each of the seven possible situations for mirrors AND/OR draw the set up

10. How to make a study game On the back of those same cards, write IN PENCIL the answers for that card

11. How to make a study game In the other columns, write the three answers each on a separate card for the situation on the left

12. How to PLAY a study game Collect all of the answer cards in a single stack and all of your setup cards in a different stack

13. How to PLAY a study game Shuffle both stacks, then deal out the setup cards in random order

14. How to PLAY a study game Place all of the answer cards on the table Turn over the setup cards and check your answers!

15. Journal #82 April 25, 2011 If you know the focal length of a concave mirror, where should you place an object so that its image is upright and larger compared to the object? Will this produce a real or virtual image? WITHOUT USING YOUR NOTEBOOK!!!

16. Journal #82 Answer Place the object between the focal point and the mirror. The image will be virtual

17. Plane Mirror Objects seen appear to be somewhere behind mirror. Eye sees the reflected light and extrapolates its path back to a point behind the mirror where it appears to originate. What you see is called a VIRTUAL IMAGE. Plane mirrors cannot produce a REAL IMAGE because parallel light rays that strike the mirror always reflect parallel to each other. Reflected light rays must intersect in order to form a REAL IMAGE. Reflection is on top of incident light

18. Characteristics of an Image: For all images, you must be able to determine the following relative to the object: Size Reduced Same Size Enlarged Orientation Upright Inverted Type of Image Real Virtual

19. For a Plane mirror object size = the image size Image orientation is the same as object (no inversion). All mirrors exhibit a left to right flip. object distance in front of the mirror = image distance behind the mirror

20. Concave Mirrors If object is placed beyond the focal point of concave mirror, all light rays from a single point on object intersect at a single point upon reflection. Light rays converging on a single point in real space will produce a REAL IMAGE because the light rays appear to be radiating from that point as they continue onward.

21. Concave Mirrors also… can create a VIRTUAL IMAGE: If object is placed closer to mirror than focal point, reflected light rays diverge. Observer would see a virtual image located somewhere behind the mirror because the light appears to originate from that point. Virtual images formed by concave mirrors are larger and farther away from the mirror than the object is. can create NO IMAGE at all when an object is placed exactly at the focal point, the reflected light rays run parallel to each other. Ex: Instead, would see a wide beam of parallel light like that of flashlight or car headlights or a completely blurry object.

22. Convex vs. Concave Mirrors

23. Convex Mirrors Virtual images formed by convex mirrors are smaller and closer to the mirror than the object is. The image is always oriented the same as the object.

24. Lens/Mirror Equation (units of length MUST match) f stands for focal length d i is the distance from the mirror/lens to the image d o is the distance from the mirror/lens to the object

25. Image Height Magnification of an image can be found by a series of ratios between the distances of objects and their images and their respective heights as shown below.

26. Helpful Hints for Mirror Probs In the formula, the numbers can tell you the characteristics of the image: Size Reduced ( |h i | < h o ) Same Size ( |h i | = h o ) Enlarged ( |h i | > h o ) Orientation Upright (h i positive) Inverted (h i negative) Type of Image Real (d i positive, in front of mirror) Virtual (d i negative, behind the mirror) Focal point for concave mirror is always positive. Focal point for convex mirror is always negative.

27. Example problem 1 A concave mirror has a radius of 28cm. An 15cm tall object is placed 25cm from the mirror. Describe the image formed. What will be the height and position of the image?

28. Example problem 2 A convex mirror has a focal length of 32cm. An 17cm tall object is placed 1.0m from the mirror. Describe the image formed. What will be the height and position of the image?

29. HW Problems P. 469 13-16 P. 472 17-21

30. P. 469

31. P. 472

32. Spherical Aberration Special Note: Parallel light rays that are far from the principal axis are not reflected by spherical mirrors to converge at the focal point. This defect is called spherical aberration. To avoid this dilemma, spherical mirrors have been replaced with parabolic mirrors in devices such as telescopes that require extreme accuracy and focus.