The Physics Factbook™
Edited by Glenn Elert -- Written by his students
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|"Electrical Energy." The New Book of Popular Science. 2000 edition. Grolier Incorporated, 1998.||"A kilowatt-hour is the electrical energy consumed in one hour at the constant rate of one kilowatt. The average household in the United States uses about 8,900 kilowatt-hours of electricity each year."||1,020 W|
|Casebolt, Cathlene. Home Alone- Living Off the Grid. Home Energy Magazine Online. (May/June 1993).||"When Bob Hammond built a house near Prescott, Arizona, he decided to get off the utility grid. To do so, he designed a home that uses only about 885 kWh of electricity a year, a fraction of the 9,300 kWh of neighboring homes. He turned to photovoltaic (PV) solar panels to generate electricity from direct sunlight, designing a 1,400 W system that is totally independent of the utility power grid."||1,060 W|
|Wohlmut, Kevin. Conserving Household Power. 21 January 2002.||"With the 'fridge on, the dial spun every 40 seconds; it spun 90 times in an hour; therefore, the whole house (including the refrigerator) was using, we estimated, 900 Watts in an hour."||900 W|
Power is defined as the rate at which work is done or energy is consumed. The formula for average power is acquired by dividing work by the time needed to perform work: P = W/t. Power has units of newton-meters per second or joules per second or watts.
The electric power produced for our residences come from power plants through a power distribution grid. The electric power derives from a power site within the power plant. The power site of a power system consists of a central mover like a turbine that is then pushed by water or steam to run a system of generators.
The amount of power that a household consumes depends on how many appliances there areand the amount of time they are in use. Some appliances or machineries take a lot of energy to operate, so it will result in more use of power.
Boi Lu -- 2003
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