| 1. | the principle that the rate of production of heat by a constant direct current is directly proportional to the resistance of the circuit and to the square of the current. |
| 2. | the principle that the internal energy of a given mass of an ideal gas is solely a function of its temperature. |
Joule's law
in electricity, mathematical description of the rate at which resistance in a circuit converts electric energy into heat energy. The English physicist James Prescott Joule discovered in 1840 that the amount of heat per second that develops in a wire carrying a current is proportional to the electrical resistance of the wire and the square of the current. He determined that the heat evolved per second is equivalent to the electric power absorbed, or the power loss.
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