unit 10: electricity and magnetism

• Electromagnet


  Temporary magnet created by wrapping a current-carrying wire (solenoid) around an iron core or other ferromagnetic material
• Ways to increase the strength of an electromagnet


  1. Increase the strength of the current

  2. Increase the number of turns of the wire
• Motor


  Electromagnetic device that converts electrical energy into kinetic energy
• Generator


  Electromagnetic device that converts kinetic energy into electrical energy
• Alternating Current


  Electric current that changes its direction repeatedly
• Direct Current


  Electric current that flows only in one direction
• electric current


  flow of electric charge (measured in units of amperes)
• circuit


  a closed conducting loop through which a current will flow
• voltage


  measure of how much electrical potential energy a battery can hold
• resistance


  measure of how difficult it is for electrons to flow through a material
• Ohm's Law


  relationship among voltage, current, and resistance in a circuit
• Electric Parameter


  • Voltage
  • Electrical current
  • Resistance
• Symbol


  • V
  • I
  • R
• Unit of Measure


  • V
  • A
  • Ω
• series circuit


  circuit that has only one path for the current to follow
• parallel circuit


  circuit that has more than one path for the current to follow
• circuit breaker


  device designed to open an overloaded circuit to prevent overheating
• electric power


  rate at which electrical energy is converted into other forms of energy
• Electric Charge


  The distribution of charge is different in conductors than it is in insulators
• Ion


  A positively or negatively charged atom
• CA+ION


  Positively charged ion
• aNion-


  Negatively charged ion
• Static charge


  Imbalance of electric charge on an object
• Electric force


  Force exerted by all charged objects
• Law of Electric Charge


  • Like charges repel and opposite charges attract
  • Electric force between two objects depends on the distance between them and the amount of charge on each object
• How an object becomes charged

  1. Friction

  2. Conduction

  3. Induction
• Friction


  Rubbing two objects together
• Conduction


  Electron transfer from one object to another through direct contact
• Induction


  Charges in an uncharged object are rearranged WITHOUT direct contact
• Electric field


  • Exists around every electric charge
  • Gets stronger as you get closer to a charge
• Conductor


  Material in which electrons can flow easily
• Insulator


  Material in which electrons can NOT easily flow
• Electric discharge


  Rapid movement of excess charge from one place to another