19.2 电动力量

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  电动力

  

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  Electrical generators convert mechanical energy into electrical energy . Every electrical needs some method for spinning the coil inside the . Hydroelectric generators use water pressure to spin the coil while windmills, of course, use the wind to spin the coil. The image here is a combination of steam turbine and generator. The steam can be produced by burning coal or diesel fuel or by a nuclear reaction and the steam then turns the coil and generates electricity.
  ::电动发电机将机械能源转换成电能。 每台电动发电机都需要用某种方法来旋转电线圈。 水电发电机需要用水压来旋转电线圈, 当然风车用风车来旋转电线圈。 这里的图像是蒸汽涡轮机和发电机的组合。 蒸汽可以通过燃烧煤炭或柴油或核反应产生, 蒸汽可以把电线圈转动并发电。

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  Electromotive Force
  
  ::电动力

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  When an individual charge flies through a magnetic field, a force is exerted on the charge and the path of the charge bends. In the case shown in the sketch below, the charge is positive and the right hand rule shows us the force will be upward, perpendicular to both the field and the path of the charge.
  ::当单个电荷飞过磁场时,电压和电压弯曲的路径就会受到力压。在下面的草图中显示的情况中,电荷是正的,右手规则告诉我们,电力会向上,与电磁场和电荷的路径垂直。

  

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  If a wire that is part of a complete is moved through a magnetic field, the force on the individual electrons in the wire occurs in exactly the same manner. Since the electrons in the wire are negatively charged, the force would be in the opposite direction but otherwise the situation is the same. When the wire is pulled downward through the magnetic field, the force on the electrons cause them to move within the wire. Since the charges are negative, the left hand rule shows that the electrons would move as diagrammed in the sketch. (Point fingers in the direction of the magnetic field, point thumb in the direction of wire movement, and palm shows direction of electron flow.) No current will flow, of course, unless the section of wire is part of a complete circuit.
  ::如果作为完整部分的电线通过磁场移动,线中单个电子的强度以完全相同的方式发生。由于电线中的电子受到负电荷,电力将朝相反的方向,但情况则相同。当电线通过磁场向下拉时,电力迫使电线在电线内移动。由于电荷为负电荷,左手规则表明电子将按绘图中的图解方式移动。 (指向磁场的方向,指向电线运动的方向,指指向电流的方向,手掌显示电流的方向。)当然,电流不会流动,除非电线的部分是整个电路的一部分。

  

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  This process allows us to convert mechanical energy (the motion of the wire) into electrical energy (the current).  This is the opposite of what happens in an where electrical energy is converted into mechanical energy.
  ::这个过程允许我们将机械能源(电线运动)转换成电能(电流 ) 。 这与电能转换成机械能源的情况相反。

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  In order to maintain a constant current flow, it is necessary to have a potential difference or in the circuit. The voltage or potential difference is also frequently referred to electromotive force . The term electromotive force, like many historical terms, is a misnomer. Electromotive force is NOT a force, it is a potential difference or per unit charge and is measured in volts. The potential difference in the case of moving a wire through a magnetic field is produced by the work done on the charges by whatever is pushing the wire through the field.
  ::为了保持恒定的电流流动,必须具有潜在差异或电路中的潜在差异。电压或潜在差异也经常被指电动力量。电动力量一词与许多历史术语一样,是一种误用。电动力量不是一种力量,而是一种潜在差异或单位电荷,用伏特计算。电动电动电动电动电动力量通过磁场移动电线的潜在差异是由电动电动电磁场的工程产生的。电动电动电动力量(与许多历史术语一样)不是一种力量,而是一种潜在差异或单位电动电动电动力量,用伏特来衡量。电动电动电动电动力量通过电磁场移动电线的潜在差异是由电动电动电动电动电动电动力量完成的工程产生的。

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  The  $\begin{array}{r}EMF\end{array}$ (or voltage) depends on the magnetic field strength, $\begin{array}{r}B\end{array}$ , the length of the wire in the magnetic field, $\begin{array}{r}l\end{array}$ , and the of the wire in the field.
  ::EMF(或电压)取决于磁场强度、B、磁场电线长度、l和电线。

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  $$\begin{array}{r}EMF=Blv\end{array}$$

  
  ::EMF=Blv

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  This calculation is based on the wire moving perpendicularly through the field. If the wire moves an angle to the field, then only the component of the wire perpendicular to the field will generate $\begin{array}{r}EMF\end{array}$ .
  ::这一计算依据是直穿田地的电线。如果电线向田地移动一个角度,那么只有与田地相连的电线组件才会产生电磁放大系数。

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  Example  
  ::示例示例示例示例

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  A 0.20 m piece of wire that is part of a complete circuit moves perpendicularly through a magnetic field whose magnetic induction is 0.0800 T. If the of the wire is 7.0 m/s, what  $\begin{array}{r}EMF\end{array}$ is induced in the wire?
  ::一个0.20米的电线,是整个电路的一部分,通过磁感应为0.0800T的磁场垂直移动。 如果电线为7.0米/秒,电线中诱导的EMF是什么?

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  $\begin{array}{r}EMF=Blv=(0.0800N/A\cdot m)(0.20m)(7.0m/s)=0.11N\cdot m/C=0.11J/C=0.11V\end{array}$
  ::EMF=Blv=(0.0800 N/Am)(0.20米)(700米/秒)=0.11 Nm/C=0.11 J/C=0.11 V

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  Further Reading
  ::继续阅读

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  Summary
  ::摘要

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  • If a wire that is part of a complete circuit is moved through a magnetic field, the magnetic field exerts a force on the individual electrons in the wire, which causes a current to flow.
    ::如果作为完整电路一部分的电线通过磁场移动,磁场对电线中的个别电子施加一种力量,造成电流流动。
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  • The potential difference in the case of moving a wire through a magnetic field is produced by the work done on the charges by whatever is pushing the wire through the field.
    ::电线在磁场移动方面的潜在差异,是由电线通过电场而完成的电荷工作产生的。
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  • The $\begin{array}{r}EMF\end{array}$ (or voltage) depends on the magnetic field strength, $\begin{array}{r}B\end{array}$ , the length of the wire in the magnetic field, $\begin{array}{r}l\end{array}$ , and the velocity of the wire in the field, $\begin{array}{r}EMF=Blv\end{array}$ .
    ::EMF(或电压)取决于磁场强度、B、磁场电线长度、l和田地电线速度,EMF=Blv。

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  Review
  ::回顾

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  1. Which of the following units are equivalent to those of  $\begin{array}{r}EMF\end{array}$  produced in a generator?
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     1. $\begin{array}{r}T\cdot m/s\end{array}$
        ::吨/吨/吨
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     2. $\begin{array}{r}V\cdot m^2/s\end{array}$
        ::Vm2/s
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     3. $\begin{array}{r}J/s\end{array}$
        ::J/秒
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     4. $\begin{array}{r}A\cdot \mathrm{\Omega }\end{array}$
        ::阿
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     5. $\begin{array}{r}T\cdot m\end{array}$
        ::Tm
     
     ::下列哪些单位相当于在发电机中生产的EMF的单位?
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  2. A straight wire 0.500 m long is moved straight up through a 0.400 T magnetic field pointed in the horizontal direction. The speed of the wire is 20.0 m/s.
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     1. What  $\begin{array}{r}EMF\end{array}$ is induced in the wire?
        ::电线中诱发的EMF是什么?
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     2. If the wire is part of a circuit with a total resistance of $\begin{array}{r}6.00\mathrm{\Omega }\end{array}$ , what is the current in the circuit?
        ::如果电线是电路的一部分 完全抗力为6.00 , 电路的电流是什么?
     
     ::直线线0.500米长通过0.400T磁场直直直移动到水平方向。 电线的速度是20. 0米/秒。 电线中导出什么EMF? 如果电线是完全抗力为6. 00 xx 的电路的一部分, 电路中的电流是什么?
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  3. A straight wire, 25.0 m long, is mounted on an airplane flying at 125 m/s. The wire moves perpendicularly through earth’s magnetic field $\begin{array}{r}(B=5.00\times {10}^{-5}T)\end{array}$ . What is the  $\begin{array}{r}EMF\end{array}$ induced in the wire?
     ::直线线25.0米长,挂在一架以125米/秒/秒飞行的飞机上。电线直穿地球磁场(B=5.00×10-5 T)。电线中导引的EMF是什么?
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  4. A straight wire, 30.0 m long, moves at 2.00 m/s perpendicularly through a 1.00 T magnetic field.
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     1. What is the induced $\begin{array}{r}EMF\end{array}$ ?
        ::诱发的EMF是什么?
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     2. If the total resistance of the circuit is $\begin{array}{r}15.0\mathrm{\Omega }\end{array}$ , what is the current in the circuit?
        ::如果电路的总阻力是15.0 °,电路的电流是什么?
     
     ::直线线,长30.0米,直线直线,直径在2.00米/秒/秒之间穿透1.00T磁场。什么是诱导的EMF?如果电路的总阻力是15.0×xx,电路的电流是什么?

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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. We have been discussing the process of generating electricity by moving a wire through a magnetic field.  What happens if the wire is held steady and the magnetic field moves instead?
     ::我们一直在讨论通过电磁场移动电线来发电的过程。 如果电线保持平稳,磁场移动,结果会怎样?
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  2. When a loop of wire is turned circularly in a magnetic field, what type of current is produced?
     ::当电线环在磁场中旋转时,会产生何种电流?