Static Electricity

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  • Created by: sophie
  • Created on: 18-11-10 07:50

Electrical Charges:

  • Inside an atom the protons and neutrons make up the nucleus and electrons about the space around the nucleus.
  • Protons have a positive charge.
  • Neutrons are uncharged.
  • Electrons have an equal negative charge.
  • An uncharged atom has equal numbers of protons and electrons. Only electrons can be transferred to or from an atom.
  • Adding electrons to an uncharged atom makes it negatively charged.
  • Removing electrons from an uncharged atom makes it positively charged.
  • Some insulators become charged by rubbing them with a dry cloth.
  • Alike charges repel and unlike charges attract.
  • Insulating materials that lose electrons when rubbed become positively charged.
  • Insulating materials that gain electrons when rubbed become negatively charged.

Summary questions:

  • When a polythene rod is charged using a dry cloth, it becomes negative because it gains electrons that transfer to it from the cloth.
  • When a perspex rod is charged using a dry cloth, it becomes positive because it loses electrons that transfer from it to the cloth.

Charge on the Move:

  • Electrical current is the rate of flow of charge.
  • Electrical current is due to electrons passing through the electrical object. This is because electrons carry negative charge.
  • If a metal object gains too much charge, it will produce sparks.
  • Metals conduct electricity because they contain conduction/ delocalised electrons, which move about freely inside the metal because they aren't confined to a single atom.
  • Insulators can't conduct electricity because all the electrons are held in atoms.
  • A conductor can only hold charge if it is insulated from the ground. If it isn't insulated, it won't hold any charge because electrons can transfer from the conductor to the ground.
  • To charge and insulated conductor, it needs to be…

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