Electrostatics

• Positiveness and Negativeness of a matter depends on the number of proton and electron.
• Charge is quantized and conserved.
• Like charges repel
• Unlike charges attract
• charging by rubbing works for insulators but not for conductors
• charging by conduction

  • charged object brought in contact with neutral object.
• charging by induction

  • negative charges leaves (or enters) object through conducting path to Earth or other limitless reservoir of charge.
• Insulators are materials in which electric charge does not move easily.
• Conductors are materials in which electric charge moves easily.
• Semi-conductors are materials that have electrical properties somewhere between conductors and insulators.
• Examples of Insulators:

  • Glass
  • Rubber
  • Plastic
  • Wood
  • Paper
• Examples of Conductors:

  • Copper
  • Silver
  • Aluminum
• Examples of Semi-conductors:

  • Silicon
  • Germanium
• Coulomb's Law

  • The amount of electric force between electric charges is directly proportional to the product of their charges but inversely proportional to the square of distance between