Electrical energy and electrical power — Define

Define the kilowatt-hour and use it to calculate the cost of using electrical appliances.

The kilowatt-hour (kWh) is the amount of energy used by an appliance with a power rating of 1 kilowatt operating for 1 hour (1 kWh = 3.6 x 10^6 J). Energy used (kWh) = power (kW) x time (hours), and the cost of using an appliance = energy used (kWh) x cost per kWh.