1 / 45

Today 1/17

Today 1/17. Interference HW: 1/17 HW Handout “Interference” Due Thur, 1/23 (beginning of class) Today’s goal: Predict locations where constructive and destructive interference occur. midpoint. This picture now includes the sources of the waves.

oren-livingston
Download Presentation

Today 1/17

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Today 1/17 • Interference • HW: 1/17 HW Handout “Interference” Due Thur, 1/23 (beginning of class) • Today’s goal:Predict locations where constructive and destructive interference occur.

  2. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  3. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  4. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  5. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  6. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  7. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  8. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  9. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  10. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  11. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  12. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  13. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  14. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  15. midpoint This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2

  16. midpoint c d c d c This picture now includes the sources of the waves. In this case the sources are in “sync” and produce waves of equal wavelength. The wave velocity depends only on the medium and so is the same for both. Source 1 Source 2 How would your answer change if the sources were out of sync? Where are the locations of constructive and destructive interference?

  17. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  18. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  19. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  20. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  21. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  22. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  23. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  24. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  25. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  26. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  27. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  28. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  29. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  30. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  31. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  32. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  33. midpoint This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Source 1 Source 2 How would your answer change if the sources were out of sync?

  34. d c d c d c d c d c Sources in phase (in sync) This picture now includes the sources of the waves. Out of sync means that one produces a crest while the other produces a trough--it’s a timing thing. Sources out of phase (out of sync) Source 1 Source 2 How would your answer change if the sources were out of sync? Now the locations for constructive and destructive interference switch!

  35. d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) In any case, the interference occurs in a pattern. The next job is to invent a rule so we can predict these locations. Sources out of phase (out of sync) Source 1 Source 2

  36. d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) What do you need to predict interference? 1. Whether the sources are in phase or not 2. Wavelength 3. Location Sources out of phase (out of sync) Source 1 Source 2

  37. PLD = 0 2   2 d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) PL1 PL2 The difference in distance from each source to constructive locations is given by... We want one thing we can say about all these places for “in phase and constructive.” PL2 - PL1 = Path Length Difference = PLD = n, n = 0,1,2,3... Sources out of phase (out of sync) Source 1 Source 2

  38. 3/2 1/2 1/2 3/2 d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) The difference in distance from each source to destructive locations is given by... Now what can we can say about the places for “in phase and destructive.” Path Length Difference = PLD = (n + 1/2), n = 0,1,2,3... Sources out of phase (out of sync) Source 1 Source 2

  39. 3/2 1/2 1/2 3/2 d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) The difference in distance from each source to constructive locations is... Path Length Difference = PLD = (n + 1/2) , n = 0,1,2,3... What about the places for “out of phase and constructive.” Sources out of phase (out of sync) Source 1 Source 2

  40. PLD = 0 d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) 2  0  2 The difference in distance from each source to destructive locations is... Path Length Difference = PLD = n, n = 0,1,2,3... What about the places for “out of phase and destructive.” Sources out of phase (out of sync) Source 1 Source 2

  41. PLD = 0 d c d c d Source 1 Source 2 c d c d c Sources in phase (in sync) Summary: In phase, constructive PLD = n, n = 0,1,2,3... In phase, destructive PLD = (n + 1/2), n = 0,1,2,3... Out of phase, constructive PLD = (n + 1/2), n = 0,1,2,3... Out of phase, destructive PLD = n, n = 0,1,2,3... Sources out of phase (out of sync) Source 1 Source 2

  42. Crest meets crest and trough meets trough, constructive, loud sound or bright light Crest meets trough and trough meets crest, destructive, no sound or dark Interference in 2-DSources “in phase” Crest Trough

  43. Constructive at a point if it is the same distance from each source Destructive at a point if it is 1/2 farther away from one source Interference in 2-DSources “in phase” Crest Trough

  44. Crest meets crest and trough meets trough, constructive, loud sound or bright Crest meets trough and trough meets crest, destructive, no sound or dark Interference in 2DSources “out of phase” Crest Trough

  45. Constructive at a point if the point is 1/2 farther away from one source Destructive at a point if the point is the same distance from each source Interference in 2-DSources “out of phase” Crest Trough

More Related