Power Ratings (OCR GCSE Physics A (Gateway)): Revision Note

Power Ratings

• The power rating of an appliance is a measure of the energy transferred per unit time

• 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 more energy is transferred per second

  • 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:

• 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

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