15.2 电场

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  A plasma globe, such as the one pictured above, is filled with a mixture of noble gases and has a high- electrode at the center. The swirling lines are electric discharge lines that connect from the inner electrode to the outer glass insulator . When a hand is placed on the surface of the globe, all the electric discharge travels directly to that hand.
  ::上面所描绘的等离子地球, 充斥着惰性气体的混合物, 在中心有一个高电极。 旋转线是从内电极到外玻璃隔热器的电排线。 当一只手放在地球表面时, 所有电排都直接流到那只手上 。

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  The Electric Field
  ::电机场

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  Coulomb’s Law gives us the formula to calculate the force exerted on a charge by another charge. On some occasions, however, a test charge suffers an electrical force with no apparent cause. That is, as observers, we cannot see or detect the original charge creating the electrical force. Michael Faraday dealt with this problem by developing the concept of an electric field . According to Faraday, a charge creates an electric field about it in all directions. If a second charge is placed at some point in the field, the second charge interacts with the field and experiences an electrical force. Thus, the interaction we observe is between the test charge and the field and a second particle at some is no longer necessary.
  ::库伦布的《库伦布法》为我们提供了计算另一种电荷强度的公式。 但是,在某些情况下,测试电荷会受到没有明显原因的电力的影响。 也就是说,作为观察者,我们无法看到或探测产生电力的原始电荷。 迈克尔·法拉第(Michael Faraday)通过发展电场的概念来解决这个问题。 根据法兰第(Faraday),电荷能产生一个全方位的电场。 如果在现场某点安装第二个电场,那么第二个电荷就会与场发生相互作用,并体验到电力。 因此,我们观察到的电荷和场之间的相互作用以及某些粒子之间的相互作用就不再必要了。

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  The strength of the electric field is determined point by point and can only be identified by the presence of test charge. When a positive test charge, q _t ,  is placed in an electric field, the field exerts a force on the charge. The field strength can be measured by dividing the force by the charge of the test charge. Electric field strength is given the symbol  $\begin{array}{r}E\end{array}$ and its unit is Newtons/coulomb.
  ::电场的强度由点点确定,只能通过测试电荷的存在来识别。当将正试验电荷(qt)放在电场时,电场对电磁力施加一定的强度。可以用测试电荷的强度除以力来测量电场的强度。电场的强度被赋予了E号符号,其单位是牛顿/库伦。

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  $$\begin{array}{r}E=\frac{F_{on{q}_t}}{q_t}\end{array}$$

  
  ::E=Fonqtqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt =Fonqt

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  The test charge can be moved from location to location within the electric field until the entire electric field has been mapped in terms of electric field intensity .
  ::试验电荷可从电场内地点移到电场内地点,直到整个电场按电场强度绘制。

   

   

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  Example  
  ::示例示例示例示例

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  A positive test charge of  $\begin{array}{r}2.0\times {10}^{-5}\text{C}\end{array}$ is placed in an electric field. The force on the test charge is 0.60 N. What is the electric field intensity at the location of the test charge?
  ::2.0x10-5C的正试验荷在电场中放置。试验荷的强度为0.60 N。试验荷位的电场强度是多少?

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  $\begin{array}{r}E=\frac{F}{q}=\frac{0.60\text{N}}{2.0\times {10}^{-5}\text{C}}=3.0\times {10}^4\text{N/C}\end{array}$
  ::E=Fq=0.60 N2.0×10-5 C=3.0×104 N/C

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  Launch the Hockey simulation below and try to use the electric field to help you score a goal:
  ::在下面启动曲棍球模拟, 并尝试使用电场来帮助您得分 :

   

   

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  Summary
  ::摘要

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  • An electric field surrounds every charge and acts on other charges in the vicinity.
    ::一个电场环绕着所有指控和附近其他指控采取行动。
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  • The strength of the electric field is given by the symbol E , and has the unit of Newtons/coulomb .
    ::电场的强度由符号E给定,并有牛顿/库伦单元。
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  • The equation for electric field intensity is $\begin{array}{r}E=\frac{F}{q}\end{array}$ .
    ::电场强度的方程式是E=Fq。

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  Review
  ::回顾

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  1. The weight of a proton is $\begin{array}{r}1.64\times {10}^{-26}\text{N}\end{array}$ .  The charge on a proton is $\begin{array}{r}+1.60\times {10}^{-19}\text{C}\end{array}$ .  If a proton is placed in a uniform electric field so that the electric force on the proton just balances its weight, what is the magnitude and direction of the field?
     ::质子的重量为1.64×10-26 N.质子的装药量为+1.60×10-19 C.如果质子放在一个统一的电场内,以便质子的电力能够平衡其重量,那么该质子的强度和方向是什么?
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  2. A negative charge of   $\begin{array}{r}2.0\times {10}^{-8}\text{C}\end{array}$ experiences a force of 0.060 N to the right in an electric field.  What is the magnitude and direction of the field?
     ::2.0x10-8C负电费在电场右侧的电力为0.060N。 电场的规模和方向是什么?
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  3. A positive charge of  $\begin{array}{r}5.0\times {10}^{-4}\text{C}\end{array}$ is in an electric field that exerts a force of  $\begin{array}{r}2.5\times {10}^{-4}\text{N}\end{array}$ on it.  What is the magnitude of the electric field at the location of the charge?
     ::5.0×10-4C正电磁场的电压为2.5×10-4N。 电磁场在电磁场的位置有多大?
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  4. If you determined the electric field intensity in a field using a test charge of  $\begin{array}{r}1.0\times {10}^{-6}\text{C}\end{array}$ and then repeated the process with a test charge of $\begin{array}{r}2.0\times {10}^{-6}\text{C}\end{array}$ , would the forces on the charges be the same?  Would this change the value for $\begin{array}{r}E\end{array}$ ?
     ::如果您使用1.0x10-6C的测试电荷确定字段的电场强度,然后用2.0x10-6C的测试电荷重复该过程,那么电荷的强度会是一样的吗?这会改变 E 值吗 ?

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  Explore More
  ::探索更多

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  Use this resource to answer the questions that follow.
  ::使用此资源回答下面的问题 。

   

   

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  1. What does it mean when a force is called a non-contact force?
     ::当一支部队被称为非接触部队时,这意味着什么?
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  2. What symbol is used to represent electric field strength?
     ::用什么符号表示电场强度 ?
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  3. What is the relationship between the direction of the electric field and the direction of the electric force? 
     ::电场方向与电力方向之间有什么关系?