calculating energy transferred by appliances

• Appliances have a power rating that tells us how many joules of energy are transferred every second
• Calculating total energy transferred

  Power in watts x Time in seconds = Energy in joules
• Appliances


  • Kettle
  • Fan
  • Iron
  • Blender
• Power rating


  Tells us how many joules of energy are transferred every second
• Normally when we have a large energy value, we convert it to kilojoules by dividing by 1,000
• Calculating energy transferred


  Power (watts) x Time (seconds) = Energy (joules)
• A fan has a power rating of 20 watts and is used for 1 hour (3600 seconds)
• An iron is used for 5 minutes (300 seconds) and transfers 600,000 joules of energy
• A blender has a power of 400 watts and transfers 48,000 joules of energy
• More practice questions on calculating energy transferred by appliances can be found in the division workbook