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*=*I*^{2}*R* - 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

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18 lessons in Physics