electricity in the homw

• A cell or a battery provides a direct current (dc).
• . The current only flows in one direction and is produced by a direct potential difference.
• Mains electricity provides an alternating current (ac)
• The current repeatedly reverses direction and is produced by an alternating potential difference.
• The positive and negative terminals of an alternating power supply swap over with a regular frequency.
• The frequency of the mains electricity supply in the UK is 50Hz and its voltage is 230V.
• The Earth wire is a safety wire to stop the appliance becoming live
• The potential difference of the Earth wire is 0V.
• The neutral wire completes the circuit
• Plastic is used for the wire coatings and plug case because it is a good electrical insulator.
• If the live wire inside an appliance touches the neutral wire a very large current flows.
• The live wire is dangerous because it has a high potential difference of 230V
• Most electrical appliances in the UK are connected to the mains using a three-core cable.
• . Copper is used for the wires because it is a good electrical conductor and it bends easily
• Why is the current provided by a cell called a direct current (d.c.)?

  only flows in one direction
• What is an alternating current (a.c.)?

  current that repeatedly reverses direction
• What kind of current is supplied by mains electricity?

  alternating current
• What is the frequency and voltage of mains electricity?

  50Hz, 230V
• What is the function of the live wire in a three-core cable?

  carries the alternating potential difference from the supply
• What is the function of the neutral wire in a three-core cable?

  completes the circuit
• What is the function of the earth wire in a three-core cable?

  safety wire to stop the appliance becoming live