1. Devil physics The baddest class on campus Pre-dp Physics

2. Lsn 11-9:. Energy transported by. waves Lsn 11-10:
Lsn 11-9: Energy transported by waves Lsn 11-10: Intensity related to amplitude and frequency

3. Questions From Reading Activity?

4. Objectives State the meaning of the term wave intensity.
Know the relationship between intensity and energy, time, area, amplitude, and radius.
Understand how intensity and amplitude vary with distance from a source that emits wave pulses spherically and for one- dimensional waves.

5. Introductory Video

6. Wave Propagation
When we study the characteristics of waves, we tend to think of them one-dimensionally
Rays instead of wavefronts

7. Wave Propagation
Most waves actually are propagated in multiple directions simultaneously
Pebble in a pond
Sound waves
Light waves

8. Wave Propagation Wave propagation is all about propagation of energy
As waves spread out, the energy also spreads out
Same energy over a larger area means a drop in intensity

9. Wave Propagation For particles exhibitying SHM,
Energy is a function of amplitude so,
The energy transported by a wave is proportional to the square of the amplitude

10. Wave Propagation
Intensity – The power (energy per unit time) transported across a unit area perpendicular to the direction of energy flow.

11. Wave Propagation
Spherical Wave – A wave that spreads out symmetrically in all directions from its source.

12. Wave Propagation

13. Wave Propagation

14. Wave Propagation

15. Wave Propagation – One-Dimension
What’s different for a one- dimensional wave like along a solid bar or within a tube?

16. Wave Propagation – One-Dimension
What’s different for a one- dimensional wave like along a solid bar or on a string?
Area remains constant
Amplitude remains constant so,
Intensity remains constant

17. Wave Propagation – Real Life
What’s different in real life?

18. Wave Propagation – Real Life
What’s different in real life?
Frictional damping
Amplitude, energy and intensity DO decrease in one dimensional waves
Intensity decreases more than the equations predict for spherical waves

19. Wave Intensity
Total energy of a wave is the sum of the energies of the individual particle in movement at any given time

20. Wave Intensity
Total energy of a wave is the sum of the energies of the individual particle in movement at any given time S
l = vt

21. Wave Intensity
Total energy of a wave is the sum of the energies of the individual particle in movement at any given time S
l = vt

22. Wave Intensity
Total energy of a wave is the sum of the energies of the individual particle in movement at any given time S
l = vt

23. Wave Intensity
Total energy of a wave is the sum of the energies of the individual particle in movement at any given time S
l = vt

24. Objectives State the meaning of the term wave intensity.
Know the relationship between intensity and energy, time, area, amplitude, and radius.
Understand how intensity and amplitude vary with distance from a source that emits wave pulses spherically and for one- dimensional waves.

25. Questions?

26. Homework
A-students, #44-45, 47-49
All others, #44-49, skip 46