2.3.2 Electrical Energy

• Electrical energy

  The energy carried by moving electrons in an electric circuit
• Conversion of electrical energy

  Electrical energy can be converted into heat, light, sound, or mechanical energy
• How electrical energy works

  1. Transferred from power source

  2. Converted into useful work or heat
• Electrical energy can be calculated using the formula: E=P×t
• E = Energy (in joules, J)
• P = Power (in watts, W)
• t = Time (in seconds, s)
• Energy calculation in practical scenarios

  Often calculated in kilowatt-hours (kWh)
• 1 kWh is the amount of energy used by a 1 kW appliance running for 1 hour
• Power (P)

  The rate at which energy is transferred or converted
• 1 watt (W) = 1 joule per second (J/s)
• Energy (E)

  The total amount of work done or heat generated over time
• Forms of energy conversion

  • Heat
  • Light
  • Sound
  • Mechanical Energy
• Efficiency

  Measures how much of the input electrical energy is converted into useful output energy
• Series Circuits


  Energy is shared among all components
• Parallel Circuits

  Each branch receives the full voltage
• Electricity companies charge consumers based on energy use, measured in kilowatt-hours (kWh)
• Battery-Powered Devices

  Batteries store electrical energy, often measured in milliampere-hours (mAh) or watt-hours (Wh)