昆明理工大学：《大学物理》课程教学资源（PPT课件，双语版）Chapter 11 磁介质中的磁场 Magnetic Field in the medium

Chapter 11 Magnetic Field in the medium 磁介质中的磁场 Fy(Magnetic Property of Matter)

Chapter 11 Magnetic Field in the Medium 磁介质中的磁场 (Magnetic Property of Matter)

8 11-1 Classifications of Magnetic Media Magnetic Permea bility 磁介质的分类磁导率 8 11-2 Molecular Theory of Paramagnetism Diamagnetism 顺磁质和抗磁质磁化的分子理论 8 11-3 Ampere's Law in the magnetic matter and magnetic intensity H 磁介质中的安培环路定理和磁场强度H 8 11-4 Ferromagnetism 铁磁质

§ 11-1 Classifications of Magnetic Media Magnetic Permeability 磁介质的分类 磁导率 § 11-2 Molecular Theory of Paramagnetism & Diamagnetism 顺磁质和抗磁质磁化的分子理论 § 11-3 Ampere’s Law in the magnetic matter and magnetic intensity H 磁介质中的安培环路定理和磁场强度H § 11-4 Ferromagnetism 铁磁质

教学要求 1.了解磁介质的磁化及其微观解释; 。、2.理解磁介质中安培环路定理的意义; 3.了解铁磁质的一些重要特性及应用。 ,,的 的的值 a22

1. 了解磁介质的磁化及其微观解释； 2. 理解磁介质中安培环路定理的意义； 3. 了解铁磁质的一些重要特性及应用。 教学要求

8 11-1 Classification of Magnetic Media and Magnetic Permeability 磁介质的分类磁导率 1 Magnetization of media介质的磁化 B B=B 0 tB 0 matter Magnetization(磁化)

B0  matter §11－1 Classification of Magnetic Media and Magnetic Permeability 磁介质的分类 磁导率 1. Magnetization of Media 介质的磁化 Magnetization(磁化） B = B + B    0

Conclusion: When a magnetic medium is brought into a magnetic field B (The matter will be magnetized; B (2) The magnetic field will matter also be influenced and changed: B=Bo+ B B' is the additional field(磁化附加场) due to the magnetization of matter and bo is the external field (pla 场)

Conclusion: When a magnetic medium is brought into a magnetic field (1)The matter will be magnetized; (2) The magnetic field will also be influenced and changed: B = B + B     is the additional field ( 磁 化 附 加 场 )due to the magnetization of matter and is the external field(外磁 场)。 B  B0  B0  matter B  

2. Classification of Magnetic media磁介质的分类 Based on the relation between B and b, the matter can be divided into three kinds: →(1) Paramagnetic substance(顺磁质):B'has same direction of B, that is B>b; (2) Diamagnetic substance(抗磁质):Bis matter opposite to Bo, that is B>b

2.Classification of Magnetic Media 磁介质的分类 Based on the relation between and , the matter can be divided into three kinds: B  B  matter (1)Paramagnetic substance(顺磁质 ): has same direction of , that is ; B  B   B  B (2) Diamagnetic substance(抗磁质）： is opposite to , that is ; B  B0  B B0  (3)Ferromagnetic substance(铁磁质): has the same direction of and ; B  B0   B  B

3. Permeability(磁导率) Take the long solenoid(长直螺线管) as an example: (●● 0 .Ooooooo.o°10o° P B 888X88888888⑧8888888888 The ratio of B and Bo is called the relative permeability of the material and represented by u B

3. Permeability（磁导率） • P  B0  0 I • P  B  0 I Take the long solenoid(长直螺线管） as an example: The ratio of B and B0 is called the relative permeability of the material and represented by :  r  = B B  r

oooooooooooo10° PB B 8888888888888888888∞8888888888888888 B0=10n B=u Bo=bou nl=anl Here u is defined as the permea bility of material. For the three kinds of magnetic substances, we have or vacuun 真空 0J0 r paramagnetic subs tance顺磁质 for diamagnetic subs tance抗磁质 Ao for ferromagnetic subs tance铁磁质

B nI 0 = 0 Here  is defined as the permeability of material. For the three kinds of magnetic substances, we have           = for ferromagnetic substance for diamagnetic substance for paramagneti c substance for vacuum 0 0 0 0      真空 顺磁质 抗磁质 铁磁质 • P  B0  0 I • P  B  0 I B B nI nI = r  =  r = 

or I for vacuum 真空 matter s1 or paramagnetic subs tance顺磁质 < I for diamagnetic subs tance抗磁质 (1 for ferromagnetic subs tance铁磁质

        =  for ferromagne tic substance for diamagneti c substance for paramagneti c substance for vacuum  r or 真空 顺磁质 抗磁质 铁磁质 matter

s 11-2 Molecular Theory of Paramagnetism Diamagnetism 顺磁质和抗磁质磁化的分子理论 1. The basic theory: ■日■口口口冒■■■■ ● Molecule 命 electron atom Charged and spin

§ 11-2 Molecular Theory of Paramagnetism & Diamagnetism 顺磁质和抗磁质磁化的分子理论 1. The basic theory: atom Molecule electron Charged and spin