2014-09-18

basics of thermodynamics-part-4

What is First law of thermodynamics?
The heat lost by a system is equal to the heat gained by the system minus any work done by the system; conservation of energy. Or

According to the first law of thermodynamics, energy cannot be created or destroyed, although it can change from one form to another.

What are the limitations of first law of thermodynamics?
First law of thermodynamics has the limitation that it merely indicates that in any process there is an exact equivalence between various forms of energy. It provides no information concerning the spontaneity or feasibility of the process.

What is Second law of thermodynamics?
Heat flows naturally from a region of higher temperature to a lower temperature. All natural systems tend toward a state of higher disorder. Or

According to the second law of thermodynamics, when energy is converted from one form to another, some of it is degraded into heat, a less usable form that disperses into the environment.

What is the second law of thermodynamics in as many ways?
Various statements of second law of thermodynamics are:
1) All spontaneous processes (or naturally occurring processes) are thermodynamically irreversible.
2) Without the help of an external agency, a spontaneous process cannot be reversed.
3) The complete conversion of heat into work is impossible without leaving some effect elsewhere.

4) The entropy of the universe is continuously increasing.

What is Carnot theorem?
It states that no heat engine operating in a cycle between two constant temperature heat reservoirs can be more efficient than a reversible engine operating between the same reservoirs.