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Joules law

JOULE LAW. The quantity of heal generated by a steady electric current is proportional to live resistance of file conductor in which the heat is generated, to Ihe square of the current, and to the lime of its duration H = KRl t. If the resistance is in ohms, the current in amperes, the lime in seconds, and the heal in calorics, the constant K has the value 0,2390 calorics/joule. [Pg.894]

PERFECT GAS. A perfect gas may be defined by the following two laws The Joule law the energy per mole, U, depends only on the temperature the Boyle law at constant temperature, the volume V7 occupied by a given number of moles of gas varies in inverse proportion to the pressure. [Pg.1223]

Let us say that electric current of density j passes through a soHd conduc tor. The local quantity of the specific power of the heat release dq/dt in unit volume of the conductor is described by the Joule law ... [Pg.64]

A material creating a resistance to electron flow introduces heating, another important phenomenon for safety engineering. The temperature of a conductor will rise as the current flow increases. The energy lost to resistance changes to heat energy, a process called Joule heating. The amount of heat produced can be determined from Joules law. [Pg.141]

According to Joules law, internal energy and enthalpy for ideal gases are functions of temperature only, u = u(T), and h = h(T). For this reason, ideal gas properties are tabulated as functions of temperature only. Entropy for an ideal gas is a function of both pressure and temperature, so property tables include s° (T), which is the entropy at the given temperature and one atmosphere of pressure. To determine entropy at other pressures, it is necessary to apply a correction to the tabulated values. [Pg.822]

Prescribe the coordinate of the current density in direction of outer normal vector on Qj part of the boundary Q = Qj u Q(o and the electric potential on Q.

vector-scalar ordered pair is the unique solution of the equations (126), which are identical(126), and uniform with the (127) transport equation. The entropy production of the system could be calculated by the Joule-law, [19],... [Pg.265]

Joule s law The internal energy of a gas depends only on its temperature (being independent of its pressure and volume). Like the other gas laws, it is only approximately true. At high pressures it is invalidated by the existence of inlermolecular forces. [Pg.229]

One may now consider how changes can be made in a system across an adiabatic wall. The first law of thermodynamics can now be stated as another generalization of experimental observation, but in an unfamiliar form the M/ork required to transform an adiabatic (thermally insulated) system, from a completely specified initial state to a completely specifiedfinal state is independent of the source of the work (mechanical, electrical, etc.) and independent of the nature of the adiabatic path. This is exactly what Joule observed the same amount of work, mechanical or electrical, was always required to bring an adiabatically enclosed volume of water from one temperature 0 to another 02. [Pg.329]

Joule s law The internal energy of a given quantity of gas depends only on its temperature and is independent of its pressure and volume. [Pg.1454]

This event marked the turning point in Joule s career. From 1847 on, when Joule spoke, scientists listened. His research results were one of the two major contributions to the establishment of the first law of thermodynamics, the other being that of the... [Pg.684]

Joule believed that nature was ultimately simple, and strove to find the simple relationships (like Joule s law in electricity), which he was convinced must exist between important physical quantities. His phenomenal success in finding such relationships in the laboratory made a crucial contribution to... [Pg.685]

In any process, we are interested not only in the direction of heat flow but also in its magnitude. We will express q in the units introduced in Chapter 6, joules and kilojoules. The joule is named for James Joule (1818-1889), who carried out very precise thermometric measurements that established the first law of thermodynamics (Section 8.7). [Pg.199]

The law was stated in this form by J. P. Joule in 1844 it is usually referred to as AVoestyn s law (1848). It shows that the carriers of heat in a solid compound are not the molecules of the latter, but the atoms of its constituent elements. Joule s law enables one to calculate the molecular heats of compounds from the atomic heats of their elements, and the atomic heats of elements in the solid state when the latter are not readily directly accessible (solid oxygen, from c(CaC03) — c-(Ca) — c(C) = 3c(0), or 100 X 0 203 — 6 4 — P8 = 3 X 4 0). [Pg.16]

According to Joule s law ( 9), the molecular heat of a compound is the sum of the atomic heats of its components, and since this holds good even when the atomic heats are irregular, i.e., not equal to 6 4, it seems that the heat content of a solid resides in its atoms, and not in the molecular complexes as such. This agrees with Einstein s theory. Hence the molecular heat of a compound should be calculable by means of the formula ... [Pg.530]

Lord Kelvin s close associate, the expert experimentalist J. P. Joule, set about to test the former s theoretical relationship and in 1859 published an extensive paper on the thermoelastic properties of various solids—metals, woods of different kinds, and, most prominent of all, natural rubber. In the half century between Gough and Joule not only was a suitable theoretical formula made available through establishment of the second law of thermodynamics, but as a result of the discovery of vulcanization (Goodyear, 1839) Joule had at his disposal a more perfectly elastic substance, vulcanized rubber, and most of his experiments were carried out on samples which had been vulcanized. He confirmed Gough s first two observations but contested the third. On stretching vulcanized rubber to twice its initial length. Joule ob-... [Pg.436]

During the next decades after the appearance of the Volta pile and of different other versions of batteries, fundamental laws of electrodynamics and electromagnetism were formulated based on experiments carried out with electric current supplied by batteries Ampere s law of interaction between electrical currents (1820), Ohm s law of proportionality between current and voltage (1827), the laws of electromagnetic induction (Faraday, 1831), Joule s law of the thermal effect of electric current, and many others. [Pg.694]

France was a center for the development of thermodynamics, the study of heat and its conversion to other forms of energy. A few years before Ril-lieux s arrival in Paris, the French physicist Sadi Carnot had published his studies of steam engines and described the principles that became the second law of thermodynamics, placing fundamental limits on how efficiently heat can be used. Within a few years, James Prescott Joule of England would lay the basis for the first law of thermodynamics stating the equivalence of heat and energy. [Pg.34]

Potential has the units of volts, i.e., joules/coulomb. An electron has lower energy in a more positive potential (closer to positive charge or farther from negative charge). Using Coulombs law, at a point 1 A distant from a proton the potential in SI units is ... [Pg.326]

William Rankine was the first to propose the first law of thermodynamics explicitly, in 1853 (he was famous for his work on steam engines). The law was already implicit in the work of other, earlier, thermodynamicists, such as Kelvin, Helmholtz and Clausius. None of these scientists sought to prove their theories experimentally only Joule published experimental proof of the first law. [Pg.85]

The first law of thermodynamics states that energy may be converted between forms, but cannot be created or destroyed. Joule was a superb experimentalist, and performed various types of work, each time generating energy in the form of heat. In one set of experiments, for example, he rotated small paddles immersed in a water trough and noted the rise in temperature. This experiment was apparently performed publicly in St Anne s Square, Manchester. Joule discerned a relationship between energy and work (symbol w). We have to perform thermodynamic work to increase the pressure within the tyre. Such work is performed every time a system alters its volume against an opposing pressure or force, or alters the pressure of a system housed within a constant volume. [Pg.86]


See other pages where Joules law is mentioned: [Pg.546]    [Pg.378]    [Pg.84]    [Pg.546]    [Pg.378]    [Pg.84]    [Pg.229]    [Pg.2951]    [Pg.179]    [Pg.307]    [Pg.93]    [Pg.237]    [Pg.265]    [Pg.282]    [Pg.684]    [Pg.684]    [Pg.684]    [Pg.778]    [Pg.841]    [Pg.1030]    [Pg.533]    [Pg.663]    [Pg.11]    [Pg.439]    [Pg.738]    [Pg.160]    [Pg.238]    [Pg.214]    [Pg.11]    [Pg.9]   
See also in sourсe #XX -- [ Pg.894 ]

See also in sourсe #XX -- [ Pg.64 ]




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