# The Kilowatt Hour: A Unit Of Energy

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Kilowatt) 1)
2) The kilowatt-hour (symbolized kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour (1 h) of time. The kilowatt-hour is not a standard unit in any formal system, but it is commonly used in electrical applications.
3) The consumption of electrical energy by homes and small businesses is usually measured in kilowatt-hours. Larger businesses and institutions sometimes use the megawatt-hour
(MWh), where 1 MWh = 1,000 kWh. The energy outputs of large power plants over long periods of time, or the energy consumption of states or nations, can be expressed in gigawatt hours (GWh), where 1 GWh = 1,000 MWh = 106 kWh.
4) The kilowatt-hour is rarely used to express energy in any form other than electrical. A quantity of gasoline, oil, or coal contains potential energy that is liberated when the fuel is burned. The heat energy resulting from combustion of such fuels is usually expressed in joules according to the International System of Units (SI) or in British thermal units (Btus) according to the foot-pound-second (fps) or English system. If this energy is used to operate an electric generator, the output of the generator over a certain period of time can be expressed in kilowatt-hours.
5) Compare watt-hour. Also see energy, joule, International System of Units (SI), and Table of Physical Units.
Reference
http://whatis.techtarget.com/definition/kilowatt-hour-kWh
British thermal unit) 6)
6) A British thermal unit (Btu) is a standard unit of energy that is used in the United States and sometimes in the U.K. It represents the amount of thermal energy necessary to raise the temperature of one pound of pure liquid water by one degree Fahrenheit at the temperature at which water has its greatest density (39 degrees Fahrenheit). The Btu is a measure in the so-called English system of units (the foot-pound-second system). Other countries use the joule, the unit of energy in the International System of Units (SI). A Btu is equivalent to approximately 1055 joules (or 1055 watt-seconds).

7) The Btu is often used as a quantitative specification for the energy-producing or energytransferring capability of heating and cooling systems such as furnaces, ovens, refrigerators, and air conditioners. The heat output of computer equipment is often specified so that it can be considered when planning the size of climate control systems in buildings. Computer device heat output is expressed in Btus per hour. 3.7 Btus per hour is equivalent to 1 watt of heat dissipation. http://whatis.techtarget.com/definition/British-thermal-unit-Btu 8) OHM
9) Ohm the standard unit of electrical resistance in the International System of Units (SI), formally defined to be the electrical resistance between two points of a conductor when a constant potential difference applied between these points produces in this conductor a current of one ampere. The resistance in ohms is numerically equal to the magnitude of the potential difference. Symbol: Ω.
10) Ohm (symbol Ω) is the electrical unit of resistance.
USED IN: measuring the resistance of an object. http://whatis.techtarget.com/definition/ohm 11) Galileo Galilei
12) In July 1609, Galileo learned about a simple telescope built by Dutch eyeglass makers, and he soon developed one of his own. In August, he demonstrated it to some Venetian merchants, who saw its value for spotting ships and gave Galileo salary to manufacture several of them. However,
Galileo’s ambition pushed him to go further, and in the fall of 1609 he made the fateful decision to turn his telescope toward the heavens. In March 1610, he published a small booklet, The Starry
Messenger, revealing his discoveries that the moon was not flat and smooth, but a sphere with mountains and craters. He found Venus had phases like the moon, proving it rotated around the sun.
He also discovered Jupiter had revolving moons, which didn’t revolve around the earth. http://www.biography.com/people/galileo-9305220 13) Stated…