1. Chapter 36 Inductance

2. + + + + + + - - - - - - Capacitance Electric energy Magnetic energy Inductance

3. Calculating the capacitance Procedure: 1.Suppose that the capacitor is charged, with ±q on the two plates respectively. 2. Find the electric field E in the region between the plates. 3. Evaluate the potential difference between the positive and negative plates, by using the formula: 4.The expected capacitance is then:

4. Calculating the Inductance Procedure: 1.Suppose i 2. Find the magnetic field B,  B 3. Evaluate the EMF by using the formula:

5. Calculating the Inductance L is independent of i and depends only on the geometry of the device.

6. a b Calculating the Inductance Calculating the capacitance a b

7. Inductance of a Toroid

8. Inductors with Magnetic Materials Ferromagnetic cores (κ m >>1, κ m =10 3 - 10 4 ) provide the means to obtain large inductances.

9. RC Circuits Combine Resistor and Capacitor in Series C  a R b Switch at position (a)(b) LR Circuits

10. RC Circuits Combine Resistor and Capacitor in Series C  a R b Switch at position (a) LR Circuits ΔV R =-iR   =L/R =L/R inductive time constant t=0, i=0 t→∞, i=ε/R.

11. RC Circuits Combine Resistor and Capacitor in Series C  a R b Switch at position (b) LR Circuits ΔV R =iR  t=0, i=0 t→∞, i=ε/R.  =L/R =L/R

12. L-C circuit Electric energyMagnetic energy Energy conservation

13. Damped and Forced oscillations If there are resistances in circuit, the U is no longer constant. Resonance

14. Energy Storage in a Magnetic Field ΔV R =-iR  i=  (dq/dt)= (  dq)/dt, the power by the emf device. i 2 R, the power consuming in the resistor. Li(di/dt), the rate at which energy is stored in the space of the inductor, it can be put out, when switch to b

15. energy is stored in the electric field energy is stored in the magnetic field inductance i UBUB i magnetic field UBUB

16. Analogy to Simple Harmonic Motion 2 2 1 kxU s  2 2 1 mvK  2 2 1 C q U E  2 2 1 LiU B 

17. Electric FieldMagnetic Field

18. Electric FieldMagnetic Field

19. Electric FieldMagnetic Field Gauss Law Ampere Law

20. Electric FieldMagnetic Field Induction

21. Electric FieldMagnetic Field

22. Electric FieldMagnetic Field

23. Example a b

24. a b

25. Exercises P839-841 9, 10, 23, 41 Problems P842 3, 5