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Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is generally supplied to businesses and homes by the electric power industry through an electric power grid. Electric power is usually sold by the kilowatt hour (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer. ==Definition== Electric power, like mechanical power, is the rate of doing work, measured in watts, and represented by the letter ''P''. The term ''wattage'' is used colloquially to mean "electric power in watts." The electric power in watts produced by an electric current ''I'' consisting of a charge of ''Q'' coulombs every ''t'' seconds passing through an electric potential (voltage) difference of ''V'' is : where :''Q'' is electric charge in coulombs :''t'' is time in seconds :''I'' is electric current in amperes :''V'' is electric potential or voltage in volts 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Electric power」の詳細全文を読む スポンサード リンク
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