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Electricity and magnetism


After this lesson, you should be able to:

  • Define power as the rate at which electrical energy transfers
  • Determine power output of a device as the product of the potential difference across the device and the current in the device
  • Apply Ohm’s law to express the power dissipated in a  device as P=I2R
  • Express the electric energy as E = Pt
  • Solve circuit problems involving the concepts of electrical power and energy
  • Know that the unit kilowatt-hour is a unit of energy relating to the cost of electricity
  • Calculate the cost of electricity in different everyday scenarios