1. 21 Electromagnetic Induction

2. Induction Experimental

3. Magnetic Flux Units: Weber (Wb) 1 Wb = 1T.m 2

4. Faraday’s Law of Induction The magnitude of the induced emf in a circuit equals the absolute value of the time rate of change of the magnetic flux through the circuit: for 1 turn or for N turns

5. Generator

6. Lenz’s Law: Against the change The direction of the any magnetically induced current or emf is such as to oppose the direction of the phenomenon causing it.

7. Lenz’s Law: Example

8. Motional Electromotive Force “-”sign: Lenz’s Law Recall Lorentz force on the moving part  I  ?

9. Eddy’s Currents

10. Application: Damping

11. Application: Speedometer

12. Application: Hybrid Generator Brake

13. Mutual Inductance Similarly, Define mutual inductance, M,

14. Self-Inductance Unit 1V.s/A = 1 Henry (H) Examples: Solenoid and Toroid

15. Transformers For an ideal transformer

16. Transformer & Eddy Current

17. Magnetic Field Energy Energy per unit volume (using solenoid)

18. R-L Circuit time  = L/R, time constant

19. L-C Circuit

20. Summary: Electromagnetic Induction & Faraday’s Law

21. Summary: Lenz’s Law

22. Summary: Motional EMF

23. Summary: Eddy’s Currents

24. Summary: Inductance

25. Summary: Transformers

26. Summary: Magnetic Energy

27. Summary: R-L & R-C Circuits

28. Homework Ch21: 1, 4, 12, 16, 21, 25, 27, 32, 40, 45, 52.

29. P9-Faraday’s Law

30. P16&17 Lenz’s law

31. P21&25-Motional emf

32. P27-Mutual Inductance

33. P32-Self-Inductance

34. P40-Transformer

35. P45-Magnetic Energy

36. Voltmeter Construction d’ V’ If the V-meter required for maximum V’ (full scale) then

37. Ammeter Construction d’ I g