Joule's laws
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Joule's laws are a set of two laws concerning the heat produced by a current and the energy dependence of an ideal gas to that of pressure, volume, and temperature, respecetively.
Joule's first law, also known as the Joule effect, is a physical law expressing the relationship between the heat generated by the current flowing through a conductor. It is named for James Prescott Joule who studied the phenomenon in the 1840s. It is expressed as:
- <math>Q = I^2 \cdot R \cdot t</math>
Where Q is the heat generated by a constant current I flowing through a conductor of electrical resistance R, for a time t. When current, resistance and time are expressed in amperes, ohms, and seconds respectively, are used the unit of Q is the joule. Joule's first law is sometimes called the Joule-Lenz law since it was later independently discovered by Heinrich Lenz. The heating effect of conductors carrying currents is known as Joule heating.
Joule's second law states that the internal energy of an ideal gas is independent of its volume and pressure, depending only only its temperature.
[edit] See also
es:Efecto Joule fr:Effet Joule it:Effetto Joule nl:Wet van Joule pt:Lei de Joule sr:Џулов закон zh:焦耳定律
