National Grid

• What is the national grid ?

  System of transformers and cables
• What is a step up transformer used for?

  Increase voltage and decrease current to reduce energy loss
• What is a step down transformer used for?

  Voltage reduction and to increase current before supplying homes and offices with electricity.
• Why is voltage reduced?

  To make it safer to use electronics connected to the mains
• a person can receive a fatal electric shock if their kite goes near to a power cable why?

  
  

  electric field strength is very high

  causing the air to become ionised

  (the kite / string) conducts charge to the person
• what is alternating potential difference?


  The voltage periodically changes from positive to negative and from negative to positive
• what is direct potential difference?


  where voltage is constant