first law of thermodynamics
qânun-e naxost-e garâtavânik
Fr.: première loi de la thermodynamique
The total energy of a → closed system is constant. This means that energy can be changed from one form to another, or transferred from one system to another, but it cannot be created or destroyed. A mathematical formulation of the first law is: δQ = δU + δW, where δQ is the heat transferred to the system, δU the change in internal energy (resulting in a rise or fall of temperature), and δW is the work done by the system.
second law of thermodynamics
qânun-e dovom-e garmâtavânik
Fr.: deuxième loi de la thermodynamique
1) Heat cannot be transferred from a colder to a hotter body without some other effect, i.e.
without → work being done. Expressed in terms of
→ entropy: the entropy of an
→ isolated system tends toward a maximum and its
available energy tends toward a minimum.
Fr.: thermodynamique statistique
Same as → statistical mechanics.
A branch of physics concerned with the relations between heat and other forms of energy and how these affect temperature, pressure, volume, mechanical action, and work.
third law of thermodynamics
qânun-e sevom-e garmâtavânik
Fr.: troisième loi de la thermodynamique
The → entropy of an idealized state of maximum order is zero at the temperature of → absolute zero. Another version of this law: As a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value.
zeroth law of thermodynamics
qânun-e sefrom-e garmâtavânik
Fr.: loi zéro de la thermodynamique
Two objects that are in → thermal equilibrium with a third object will be in thermal equilibrium with each other.