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  • 《伦兹法》

    A Hand-Cranked Generator With A Bulb, Illustrating Lenz'S Law And Electric Current Generation.

    This is a diagram of a hand-cranked demonstration . Turning the hand crank spins a coil inside horseshoe magnets and generates an electric current that lights the bulb. In order to generate an electric current in a conductor , the conductor must be part of a complete . If the light bulb is removed from this apparatus, the crank is very easy to turn. If the light bulb is absent, the circuit is incomplete and no current is generated. When the light bulb is place in the circuit, the circuit is complete and turning the crank will generate a current and light the bulb. When the crank is turned with bulb in the circuit, it is more difficult to turn the crank. A great deal more effort is needed to turn the crank while current is generated. 
    ::这是手排演示的图表 。 手动曲柄在马蹄铁磁铁内旋转卷圈, 并生成电流来点灯泡。 为了在导电器中产生电流, 指挥器必须是完整的一部分 。 如果灯泡从此设备中移除, 曲柄很容易转动 。 如果没有灯泡, 电路就不完整, 没有电流。 当灯泡在电路中放置时, 电路是完整的, 转动曲柄将产生电流和灯泡。 当电路中用灯泡转换曲柄时, 转动曲柄比较困难 。 在电流产生时, 需要付出更大的努力来转动曲柄 。

    Lenz’s Law

    ::伦兹法律

    In the sketch below, moving the wire downward through the causes electrons to flow in the wire as diagrammed. This is because relative motion between charged particles and magnetic fields produces a force on the charged particles . . . so the downward movement of the wire causes a force which moves the electrons, producing a current. When the electrons begin to flow, however, there is a second motion of the charged particles and this second motion will produce a second force on the particles.
    ::在下面的草图中,通过电线向下移动,导致电子以图解方式在电线中流动。这是因为电荷粒子和磁场之间的相对运动产生对电荷粒子的威力.因此电线向下移动产生电动,从而产生电流。然而,当电子开始流动时,有电量粒子的第二次运动,而这一第二次运动将产生对电磁粒的第二次威力。

    A wire is shown moving downward, indicating electron flow upwards in a magnetic field.

    If we use the left hand rule on the electron flow, we point our fingers in the direction of the field and our thumb in the direction of electron movement and the palm of our hand indicates the direction of the force – UP !
    ::如果用左手规则处理电子流动, 我们用手指指向田野的方向, 用拇指指指向电子运动的方向,

    This secondary force always opposes the first movement of the wire. Lenz’s law states the induced current produces a magnetic field that opposes the motion that caused the induced current.
    ::这种二次力量总是反对电线的首次移动。 伦兹的法律指出,引流会产生磁场,而引流则会产生磁场,而驱动电流的运动则会因此产生反作用。

    “An induced generates a current that induces a counter magnetic field that opposes the magnetic field generating the current.”
    ::“诱导产生电流,引发反磁场,对抗产生电流的磁场。”

    Lenz’s law also applies to electric motors. When an EMF is sent through a motor (aka, a current is passed through the armature of a motor) a force is produced that causes the armature to turn. This is electric converted to mechanical energy . The spin of the armature, however, now causes the motor to act like a generator and generate an EMF. The direction of the EMF is always the opposite of the original EMF that was sent through the motor. This second EMF is called back-EMF .
    ::Lenz的法律也适用于电动机。当EMF通过马达发送时(又称电流通过马达的臂章传递),就会产生一种力量,使电动转为机械能源。这是电转换成机械能源。但是,电动动力的旋转现在导致电动发动机像发电机一样,产生EMF。EMF的方向总是与通过马达发送的原始EMF相反。第二个EMF被称作回调-EMF。

    Summary
    ::摘要

    • Lenz’s law states, “An induced electromotive force generates a current that induces a counter magnetic field that opposes the magnetic field generating the current.”
      ::伦兹的法律规定 : “ 诱导电动力产生电流,引发反磁场,对抗产生电流的磁场。 ”
    • The spin of the armature, however, now causes the motor to act like a generator and generate an EMF. The direction of the EMF is always the opposite to the original EMF that was sent through the motor.
      ::电磁场的方向总是与最初通过电机发送的电磁场相反。

    Review
    ::回顾

    Consider the sketch below where two magnets are being held above two wire coils. When dropped the magnet on the  left will pass through the coil while the magnet on the right will pass in front of the coil.
    ::考虑下方两块磁铁在两根铁丝圈上方的草图。 当磁铁落在左侧时, 磁铁会穿过圆圈, 而右侧的磁铁会在圆圈前通过 。

    Sketch showing two magnets above coils: one inside and one in front. Lenz's Law concept.

    Left: A magnet will be dropped through a coil of wire. Right: A magnet will be dropped in front of a coil of wire.
    ::左: 磁铁会通过电线圈投下。 右: 磁铁会投在电线圈前 。

    1. Will a current be induced in the coil on the right when the magnet  is droppe d ?
      1. Yes
        ::是 是
      2. No
        ::否 无

      ::当磁铁被丢弃时, 电流是否会在右侧的圈圈内导出? 是 否
    2. Will a current be induced in the coil on the left when the magnet  is dropped ?
      1. Yes
        ::是 是
      2. No
        ::否 无

      ::当磁铁被丢弃时, 电流是否会在左侧的圆圈中导出 ? 是 否
    3. If a current is induced in one of the coils when the magnet passes through, which way will the current flow?
      1. clockwise
        ::时顺时针
      2. counterclockwise
        ::逆时针反时针

      ::如果电流在磁磁通过时的圈圈中被导出, 流流会以哪种方式流? 顺时针顺时针顺时针
    4. If both magnets are dropped at the same time, which magnet would reach the ground first?
      1. the one on the left
        ::左边那个
      2. the one on the right
        ::右边右边那个
      3. they would hit the ground at the same time
        ::他们将同时撞倒地面

      ::如果两个磁铁同时投下, 哪个磁铁会先到达地面? 左边的磁铁会同时撞击地面。
    5. Will a hand generator be more difficult to turn when it is generating current or when it is not generating current?
      1. generating
        ::生成
      2. not generating
        ::不生成

      ::当一个手动发电机产生电流或当它不产生电流时,它会更难转弯吗?

    Explore More
    ::探索更多

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

    1. In general, how would the observation change if the aluminum tube were replaced with a copper tube?
      ::一般而言,如果铝管换成铜管,观察结果会如何改变?
    2. In general, how would the observation change if the glass tube were replaced with a copper tube?
      ::一般而言,如果用铜管取代玻璃管,观察结果会如何改变?