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James Prescott Joule (/ dʒ uː l /; [1] [2] [a] 24 December 1818 – 11 October 1889) was an English physicist. Joule studied the nature of heat and discovered its relationship to mechanical work . This led to the law of conservation of energy , which in turn led to the development of the first law of thermodynamics .
To distinguish these two thermal expansion equations of state, the latter one is called pressure-dependent thermal expansion equation of state. To deveop the pressure-dependent thermal expansion equation of state, in an compression process at room temperature from (V 0, T 0, P 0) to (V 1, T 0,P 1), a general form of volume is expressed as
Joule's apparatus for measuring the mechanical equivalent of heat. Most established scientists, such as William Henry, [13] as well as Thomas Thomson, believed that there was enough uncertainty in the caloric theory to allow its adaptation to account for the new results. It had certainly proved robust and adaptable up to that time.
Quantity (common name/s) (Common) symbol/s Defining equation SI unit Dimension Temperature gradient: No standard symbol K⋅m −1: ΘL −1: Thermal conduction rate, thermal current, thermal/heat flux, thermal power transfer
The first and second law of thermodynamics are the most fundamental equations of thermodynamics. They may be combined into what is known as fundamental thermodynamic relation which describes all of the changes of thermodynamic state functions of a system of uniform temperature and pressure.
1852 – Joule and Thomson demonstrate that a rapidly expanding gas cools, later named the Joule–Thomson effect or Joule–Kelvin effect; 1854 – Helmholtz puts forward the idea of the heat death of the universe; 1854 – Clausius establishes the importance of dQ/T (Clausius's theorem), but does not yet name the quantity
The net work equals the area inside because it is (a) the Riemann sum of work done on the substance due to expansion, minus (b) the work done to re-compress. Because the net variation in state properties during a thermodynamic cycle is zero, it forms a closed loop on a P-V diagram.
An irreversible process increases the total entropy of the system and its surroundings. The second law of thermodynamics can be used to determine whether a hypothetical process is reversible or not. Intuitively, a process is reversible if there is no dissipation. For example, Joule expansion is irreversible because initially the system is not ...