Calculating Energy Transferred by Appliances

• What should you be able to calculate by the end of this video?

  Energy transferred by electrical appliances
• What do appliances transfer electrical energy into?

  Kinetic energy and thermal energy
• What does the power rating of an appliance indicate?

  Energy transferred every second
• How do you calculate total energy transferred using power ratings?

  Multiply power by time
• What is the power rating of the kettle in the example?

  2,200 watts
• How long is the kettle used in the example?

  80 seconds
• What is the equation used to calculate energy in joules?

  Energy (J) = Power (W) × Time (s)
• What is the total energy transferred by the kettle?

  176,000 joules
• How do you convert joules to kilojoules?

  Divide by 1,000
• What is the final energy value for the kettle in kilojoules?

  176 kJ
• What is the power rating of the fan in the example?

  20 watts
• How long is the fan used for in the example?

  1 hour
• How many seconds are in 1 hour?

  3,600 seconds
• What is the total energy transferred by the fan?

  72,000 joules
• What is the total energy transferred by the iron?

  600,000 joules
• How long is the iron used for in the example?

  5 minutes
• How many seconds are in 5 minutes?

  300 seconds
• How do you calculate the power of the iron?

  Power = Energy / Time
• What is the power of the iron calculated in the example?

  2,000 watts
• What is the power rating of the blender in the example?

  400 watts
• What is the total energy transferred by the blender?

  48,000 joules
• How do you calculate the time the blender is used for?

  Time = Energy / Power
• What is the time the blender is used for?

  120 seconds
• What is the process to calculate energy transferred by appliances?

  1. Identify power rating in watts
  2. Identify time in seconds
  3. Use the equation: Energy (J) = Power (W) × Time (s)
  4. Convert joules to kilojoules if necessary
• What are the key units used in energy calculations?

  • Power: Watts (W)
  • Energy: Joules (J) or Kilojoules (kJ)
  • Time: Seconds (s)
• What are the steps to convert energy from joules to kilojoules?

  1. Take the energy value in joules
  2. Divide by 1,000
  3. Result is in kilojoules