AQA GCSE Physics

Revision Notes

2.3.4 Power Ratings

Power Ratings

  • The power of an appliance is the amount of energy it transfers by electrical work every second
    • This is normally the transfer of an electrical energy store to other energy stores, depending on the appliance
  • Every electrical appliance has a power rating which tells you how much electricity it needs to work
    • For example, a washing machine will require a lot more electricity than an iron because it is much heavier and more powerful
  • The power rating for domestic electrical appliances is normally given on a label. This will include:
    • The potential difference required to make the device work (eg. 230 V in the UK)
    • The frequency of the supply (eg. 50 Hz in the UK)
    • The power rating in Watts (this varies for each device)
  • The higher the power rating, the quicker the change in stored energy
    • For example, a 2000 W kettle means the kettle transfers 2000 J of energy per second from one store to another
  • The different power ratings of various household appliances are listed in the table below as examples:

Power of Household Appliances Table, downloadable IGCSE & GCSE Physics revision notes

  • Care must be taken not to plug an appliance into a mains that is has a voltage that is much higher than stated on the label, for example in another country that has a higher mains voltage
    • This could cause the appliance to fuse or set fire and become damaged

power-rating, IGCSE & GCSE Physics revision notes

Mains electric appliances, such as this kettle, are fitted with labels that list important information such as the power and voltage of the appliance

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