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joule
joule , abbr. J, unit of work or energy in the mks system of units, which is based on the metric system ; it is the work done or energy expended by a force of 1 newton acting through a distance of 1 meter. The joule is named for James P. Joule.
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James Prescott Joule
James Prescott Joule , 1818-89, English physicist. His scientific researches began in his youth when he invented an electromagnetic engine. Joule made valuable contributions to the fields of heat, electricity, and thermodynamics. His work established the mechanical theory of heat , and he was the f...
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erg
erg , unit of work or energy in the cgs system of units, which is based on the metric system ; it is the work done or energy expended by a force of 1 dyne acting through a distance of 1 centimeter. In terms of the joule , the unit of work or energy in the mks system, 1 erg equals 0.0000001 j...
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thermoelectricity
thermoelectricity direct conversion of heat into electric energy, or vice versa. The term is generally restricted to the irreversible conversion of electricity into heat described by the English physicist James P. Joule and to three reversible effects named for Seebeck, Peltier, and Thomson, their ...
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power
power in physics, time rate of doing work or of producing or expending energy . The unit of power based on the English units of measurement is the horsepower , devised for describing mechanical power by James Watt, who estimated that a horse can do 550 ft-lb of work per sec; a foot-pound is the...
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watt
watt [for James Watt ], abbr. W, unit of power, or work done per unit time, equal to 1 joule per second. It is used as a measure of electrical and mechanical power. One watt is the amount of power that is delivered to a component of an electric circuit when a current of 1 ampere flows through the ...
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British thermal unit
British thermal unit abbr. Btu, unit for measuring heat quantity in the customary system of English units of measurement , equal to the amount of heat required to raise the temperature of one pound of water at its maximum density [which occurs at a temperature of 39.1 degrees Fahrenheit (°F)&t...
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Nicolas Léonard Sadi Carnot
Nicolas Léonard Sadi Carnot , 1796-1832, French physicist, a founder of modern thermodynamics; son of Lazare N. M. Carnot. His famous work on the motive power of heat ( Réflexions sur la puissance motrice du feu, 1824) is concerned with the relation between heat and mechanical energy....
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green flash
green flash or emerald flash, a refractive phenomenon of the atmosphere where the top edge of the setting (or, less frequently, rising) sun will momentarily turn emerald green. The green color lasts from a fraction of a second to two seconds. It is usually seen over a low distant horizon, such ...
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heat capacity
heat capacity or thermal capacity, ratio of the change in heat energy of a unit mass of a substance to the change in temperature of the substance; like its melting point or boiling point, the heat capacity is a characteristic of a substance. The measurement of heat and heat capacity is call...
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