2. Chapter 34 The Wave Nature of Light (physical optics) http://images.google.com/images?q=iridescense&rls=c om.microsoft:en-us&oe=UTF- 8&startIndex=&startPage=1&um=1&ie=UTF- 8&sa=N&hl=en&tab=wi

3. Introduction Our Approach –Gain more precision about waves –Look at refraction from a wave perspective –Understand the double-slit interference pattern –Understand reflection from thin films

4. More precision on waves What are the differences between waves and particles? (question/discussion) Draw the wave fronts and rays for several waves: waves emanating from a point, waves in the interior of a beam, waves converging to a point. (on whiteboards) Look at the (approximate) explanation of the propagation of waves according to the Huygen’s Principle.

5. Refraction (a wave perspective) What is the key diagram used to derive the law of refraction from a wave perspective? (And then the derivation.) How do the wavelength, frequency, and speed of waves change as the light goes from a material with index of refraction n 1 to material with index of refraction n 2 ? linklink http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=16 Other explanations of refraction: Newton’s particle model, principle of least time

6. Double-slit interference pattern Whiteboard exercise linklink What relationship between path lengths produces destructive interference? What relationship between path lengths produces constructive interference? Constructive interference is at what angles on a screen far away from the slits? Destructive interference is at what angles on a screen far away from the slits? http://id.mind.net/~zona/mstm/physics/waves/interference/twoSourc e/TwoSourceInterference1.htmlhttp://id.mind.net/~zona/mstm/physics/waves/interference/twoSourc e/TwoSourceInterference1.html

7. Reflection from thin films What analogy is particularly helpful in grasping the options for changes of phase of light upon reflection? When does light shift in phase by 180 0 during reflection? Does the phase change during transmission?

8. …thin films (cont’d.)… What diagram is especially useful for organizing one’s thinking for determining constructive and destructive interference from a thin film? What two general factors determine whether reflection from a thin film is constructive or destructive?

9. the end

10. fill in the chart backback 1n1n1 n2n2 vc ff0f0 λλ0λ0

11. whiteboard exercise backback On left side of whiteboard draw a vertical line with two small openings representing slits (in and out of page) approximately 20 cm apart. Draw at random two points, one above and one below the horizontal line midway between the slits. Assuming a wavelength of 10cm, will the waves interfere (approximately) constructively, destructively, or neither at these points?