3.7.6

Domestic Uses of Electricity

Test yourself

Power Rating of Appliances

Appliances in the EU have a label or panel that tells you what the power rating of the appliance is.

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Power label

  • This power label can be used to calculate the current required by the appliance using the equation:
    • power = potential difference x current.
    • power = current 2 x resistance.
  • 230 V is the potential difference across the mains power supply in the UK.
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Work done per second

  • We can work out how much energy an appliance transfers using the power rating and the equation:
    • energy transferred = power x time.
    • energy transferred = charge x potential difference.
  • For example, a 100W lamp will use 100J of energy each second.

National Grid

The National Grid is the network of cables and transformers that connect power stations with houses and shops in the United Kingdom.

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Power stations

  • Power stations create an electric current, which is an energy carrier.
    • Large power stations are more efficient than smaller power stations because they can burn lots of fuel at very high temperatures. This creates very hot steam that can turn the turbines.
    • Steam turbines are more efficient at higher temperatures.
  • Power stations produce electricity at a voltage of 25,000 Volts.
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Step-up transformers

  • Step-up transformers then increase the potential difference to 400,000 Volts.
    • This reduces the current and this reduces how much heat is lost when it’s being transported across the country.
    • This increases the efficiency of the National Grid system.
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Step-down transformers and our homes

  • To get electricity to a safer voltage (230 Volts) in our homes, step-down transformers reduce the voltage to a lower value.

Jump to other topics

1Principles of Science I

1.1Structure & Bonding

1.2Properties of Substances

1.3Cell Structure & Function

1.4Cell Specialisation

1.5Tissue Structure & Function

1.6Working with Waves

1.7Waves in Communication

2Practical Scientific Procedures and Techniques

3Science Investigation Skills

4Principles of Science II

4.1Extracting Elements

4.2Relating Properties to use of Substances

4.3Organic Chemistry

4.4Energy Changes in Industry

4.5The Circulatory System

4.6Ventilation & Gas Exchange

4.7Urinary System

4.8Cell Transport

4.9Thermal Physics

4.10Materials

4.11Fluids

5Contemporary Issues in Science

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