Friday, October 1, 2010

Law Of Thermodynamics

There are three laws of thermodynamics.

1. Zeroth Law of Thermodynamics.
                                  This law states, "when two systems are each in the thermal equilibrium with a  third system, then the two systems are also in thermal equilibrium with one another."

2. First aw of Thermodynamics.
  This law states, "The heat and mechanical work are mutually convertible."
3. Second Law Of Thermodynamics.
                                  The second law of thermodynamics may be defined in many ways. but the two common statements according Kelvin-Plank and  Clausius are good.. in fig you can learn the second law yourself..

Thermal or Heat Capacity

The thermal or heat capacity of a substance may be defined as the heat required to raise the temperature of whole mass of a substance through one degree. Mathematically,
                      Thermal or heat capacity = mc KJ
                        m = Mass of the substance in kg
                   c = Specific heat of the substance in kJ/kgK.

Thermodynamic Equilibrium

A system is said to be in thermodynamic equilibrium, if it satisfied the following three requirements of equilibrium.

1. Mechanical equilibrium. A system is said to be in mechanical equilibrium, when there is no unbalanced forces acting on any part of the system.
2. Thermal equilibrium. A system is said to be in thermal equilibrium, when there is no temperature difference between the parts of the system.
3. Chemical equilibrium. A system is said to be in chemical equilibrium, when there is no chemical reaction with the system.