Chapter 19 review


    Vocabulary
    Match each word to the sentence where it best fits.
      Section 19.1

      armature commutator
      electric motor electromagnetism
      electromagnets polarity
      solenoid 
      1. When you identify which end of a magnet is north you have determined its _______.
      2. As an electrical device rotates about its axis, the curved plates that create alternating voltages are called the _______.
      3. The subject of _______ connects the flow of electricity to the magnetic force.
      4. _______ can be created by wrapping wires carrying electricity around a metal nail.
      5. When Ravi wrapped a long wire around a cardboard tube he was creating a/an _______.
      6. The part of an electrical device that has rotating electromagnets is the _______.
      7. The _______ converts electrical energy into rotational motion of its axle.
      Section 19.2

      Faraday’s law of induction Lenz’s law
      electrical generator electromagnetic induction
      magnetic flux transformer
      1. A hydroelectric power plant has a/an _______ that converts the rotational motion of the turbines into electricity.
      2. Electricity from a hydroelectric power plant is usually converted to high voltage using a/an _______.
      3. The _______ is a measure of the amount of magnetic field that passes through a closed loop of wire.
      1. Voltage can be created in a conductor by nearby, changing magnetic flux in a process called _______.
      2. That a changing magnetic field through a loop of 10 wire coils will induce more current than the same changing magnetic field through a loop of 3 wire coils is a consequence of ________.
      3. That an induced current flows in the direction to oppose a changing magnetic flux follows from ________.
      Section 19.3

      cathode ray tube (CRT) cyclotron radius
      galvanometer mass spectrometer
      permeability of free space voice coil
      1. The _______ is a scientific instrument that can determine what elements are present in a gas.
      2. An indication of how well a magnetic field can be established in a vacuum is called the ________.
      3. Older kinds of television sets and computer monitors use a _______ to form the picture.
      4. In a bubble chamber image, the _______ can be used to determine the mass and charge of a particle.
      5. A scientific instrument that is a sensitive detector of small electric currents is the _______.
      6. At the heart of a loudspeaker is the _______, which moves up and down in response to changing electric current through it.
      Conceptual questions
        Section 19.1
          Bar magnet near a coil of wire carrying electric current
        1. Easy A coil of wire carries a current as shown in the diagram. Will the bar magnet be attracted or repelled by the coil?

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