1. Lenses, Ray diagrams, CNs Wednesday, April 20, 2015

2. Unit 8: EM Spectrum/Optics Wednesday, 3/4 Draw the mirrors below and label them (concave, convex) Upcoming dates:  Monday, 4/18 – EM Spectrum/Optics quiz – cancelled only one quiz this unit  Thursday, 4/21 – Last day to re-test on Waves  Tuesday, 4/26 - EM Spectrum/Optics quiz  Thursday, 4/28 – EM Spectrum/Optics test all missing EM Spectrum/Optics work is due (missing work is a zero after you test)  Friday, 5/6 – Atomic Physics test all missing Atomic physics work is due (missing work is a zero after you test)  Monday, 5/16 – Rube Goldberg Project due (test grade)  Friday, 5/20 – Bottle Rocket launch day (test grade)  Thursday, 5/26 – Exam review due (it is 30% of your exam grade)

3. Warm-up answer

4. Introduction to lenses  On the back table you will find two different shaped lenses.  Place the lenses in front of the light source and observe what the light ray does.  You will trace the the incoming and outgoing (show me your rays before tracing).  Trace the rays on the paper provided (we will be adding notes to your diagrams.

5. CNs

6. Convex Lens

7. Concave Lens

8. Ray Diagrams  Diagraming the light rays from an object allow us to predict the image we see.  Location of the image  Real or virtual  Orientation; upright or inverted  Size; enlarged, same size, reduced)  We will do this for convex lenses only!

9. Setting up the principal axis

10. Rules for Drawing Ray Diagrams Note: the point where the lines intersect is the image location. Darken in that point (point becomes the tip of the arrow)

11. Example 1

12. Example 2

13. Example 3

14. Example 4

15. Example 5

16. CNs – Lens Equation Focal length (cm) Distance of object (cm) Distance of image (cm)

17. CNs – Magnification Equation Object magnification (cm) Height of image (cm) Distance of image (cm) Distance of Object (cm) Height of object (cm)

18. Practice questions

19. Cool Down  If the magnification is a negative number what does it tell you about the size of the image compared to the actual size of the object?