今日分享（十一）如何学好大学物理（5）——电磁学

今日分享（十一）如何学好大学物理（5）----电磁学

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今天小编为大家带来今日分享（十一），欢迎您的访问！

Share interests, spread happiness, increase knowledge,

and leave a good legacy!

Dear you, this is The LearningYard Academy.

Today Xiaobian brings you today's sharing (eleven), welcome your visit!

电荷

电荷：电荷是自然界中粒子的一种基本属性。电荷有两种，分别称为正电荷和负电荷。自然界的粒子所带的电荷不能无限小，一个基本的电荷量是指电子所带的电量，数量为 e=1.6×10的－19次方

Charge: Charge is a fundamental property of particles in nature. There are two types of charges, called positive and negative charges. The charge carried by particles in nature cannot be infinitely small, and a basic amount of charge refers to the amount of electricity carried by electrons, which is e=1.6×10 to the power of -19

点电荷：点电荷是指大小和形状可以忽略，可以看成一个点的带电体。同质点一样，是否能被看作点电荷，也依具体问题而定。

Point charge: Point charge refers to a charged body whose size and shape can be ignored and can be seen as a point. Whether or not it can be regarded as a point charge, like the homogeneous point, depends on the specific problem.

库仑定律：同种电荷相互排斥，异种电荷相互吸引。真空中，两个点电荷之间的相互作用力沿着二者连线的方向。

Coulomb's law: The same charge repels each other, and the different charges attract each other. In a vacuum, the interaction force between the charges of the two points follows the direction of the connection between the two.

试验电荷：为了尽量减少因为电场力过大，而导致场源电荷重新分布，进而影响空间电场的分布，基于点电荷的模型，定义所谓“试验电荷”，即带电量足够小的点电荷。

Test charge: In order to minimize the redistribution of the field source charge due to the excessive electric field force, which in turn affects the distribution of the spatial electric field, based on the model of the point charge, the so-called "test charge" is defined, that is, the point charge with a sufficiently small amount of charge.

电场与场强

电场强度：试验电荷在空间某点所受到的电场力与试验电荷的量的比值，其方向与该点正电荷受力方向一致

Electric Field Strength: The ratio of the electric field force received by the test charge at a certain point in space to the amount of the test charge, and its direction is consistent with the direction of the positive charge at that point

电场线：一种描述电场强度矢量分布的模型，它在某处的切线方向对应该点的电场的方向，在某点垂直于电场的单位面积内，穿过的电场线的条数 N为该处电场强度的大小 E

Electric field line: A model that describes the vector distribution of electric field intensity, which corresponds to the direction of the electric field at the corresponding point in the tangent direction of a certain point, and within the unit area perpendicular to the electric field at a certain point, the number of electric field lines passing through N is the size of the electric field strength at that place E

电场线特点：起始于正电荷或无穷远，终止于负电荷或无穷远。电场线永不相交，不会在没有电荷的地方中断。

Electric field line characteristics: starts with positive charge or infinity, ends at negative charge or infinity. The electric field lines never intersect and are not interrupted where there is no charge.

电通量：根据以上电场线的模型易知

Electric flux: It is easy to know according to the model of the above electric field line

高斯定理

真空中，穿过任意闭合曲面的电场强度的通量 ，等于该曲面内所包含的电荷的代数和

高斯定理表明，电荷是电场的源，电场是有源场。

In a vacuum, the flux of the electric field intensity through any closed surface is equal to the algebraic sum of the charges contained within that surface

Gauss's theorem states that charge is the source of an electric field, and an electric field is a source field.

注：

• 闭合曲面外的电荷对整个曲面上的电通量没有贡献，曲面上的的电通量全部由内部的电荷贡献。
• 高斯定理描述的是曲面的通量与内部的电荷之间的关系，并不是描述曲面上的电场与电荷之间的关系。
• 高斯面上的电场并非只由曲面内的电荷贡献，而是由空间所有电荷共同贡献的。
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• The charge outside the closed surface does not contribute to the electrical flux on the entire surface, and the electrical flux on the surface is all contributed by the internal charge.
• Gauss's theorem describes the relationship between the flux of a surface and the internal charge, not the relationship between the electric field and the charge on the surface.
• The electric field on a Gaussian surface is not contributed only by the charge within the surface, but by all the charges in space.