ZEROTH LAW OF THERMODYNAMICS
*This law states that "When the two systems are, each in thermal equilibrium with a third system, the two systems are also in thermal equilibrium with one another".
*This law provides the basis of temperature measurement.
FIRST LAW OF THERMODYNAMICS
*First law of thermodynamics based on law of conservation of energy according to which the total amount of energy in any thermodynamic system remains constant.
*Energy cannot be produced (or) destroyed, it can only be converted from one form to another.
*It states that "Heat and work are mutually convertible but since energy can neither be created not destroyed, the total energy associated with an energy conversion remains constant".
(or)
*It states that "No machine can produce energy without corresponding expenditure of energy.
SECOND LAW OF THERMODYNAMICS
*This law has been mentioned by two statements, Clausius and Kelvin-Planck statements. Each statement is based on irreversible process.
1) Clausius Statement
2) Kelvin - Planck Statement
1)Clausius Statement
It states that "It is impossible for a self acting machine working in a cyclic process unaided by any external agency, to convey heat from a body at a lower temperature to a body at a higher temperature".
(or)
Its states that "That it is impossible to construct the device that operates in a cycle and produces no effect other than the transfer of heat from a lower temperature body to a higher temperature body".
2)Kelvin - Planck statement
It states that "It is impossible construct the engine operating on a cycle whose sole effect is transfer of heat energy from a single heat reservoir and do equivalent amount of work".
(or)
*It is not possible to convert all the heat supplied to a heat engine into useful work. That means, 100% efficiency of an engine is not possible.
*A certain amount of heat has to be necessarily rejected to a low temperature reservoir.
THIRD LAW OF THERMODYNAMICS
It states that "entropy of all perfect crystalline solids is zero at absolute zero temperature". It means that at zero entropy datum is chosen at 0°C (or) 273 K.
FOURTH LAW OF THERMODYNAMICS
