<u>First law of thermodynamics:</u>
- It states that <em>"Energy neither be created nor it can be destroyed". </em>simply it converts one form of energy into another form.
- It is also known as<em> "law of conservation of energy"</em>
<u>Limitations of First law</u>
- It doesn't provide a clear idea about the direction of transfer of heat.
- It doesn't provide the information that how much heat energy converted inti work.
- Its not given any practical applications.
<u>II law of thermodynamics:</u>
It states that <em>"the total entropy of the system can never decrease over time"</em>
It is strongly proved by two laws, they are
<em>1. Kelvin-plank statement:</em>
He stated that "any engine does not give 100% efficiency". It violates the Perpetual motion of machine II kind<em>(PMM-II).</em>
<em>2. Classius statement: </em>
<em> </em><em> It states that "Heat always flows from high temperature body to low temperature body, without aid of external energy". </em>
<em> Also it stated that " Heat can also be transferred from low temperature body to high temperature body, by the aid of an external energy".</em>
<em>Applications of II law: </em>
<em>Refrigeration &Air conditioning, Heat transfer, I.C. engines, etc.</em>
