Question

State the various statements of Second law of Thermodynamics.

Answer 1

Statements of second law of thermodynamic:
(i) Kelvin-Planck statement : "It is impossible to construct an engine which operated in a complete cycle will absorb heat from a single body and convert it completely to work without leaving some changes in the working system".
(ii) Clausius statement: "It is impossible to transfer heat from a cold body to a hot body by a machine without doing some work".
(iii) Entropy statement: "A process accompanied by increase in entropy tends to be spontaneous".
(iv) According to efficiency measurement: "Efficiency of a machine can never be cent percent".
(v) According to II law of themodynamics: The heat Efficiency of any machine is given by the value of ratio of output to input energies. Output can be in the form of any measurable energy or temperature change while input can be in the form of heat energy or fuel amount which can be converted to heat energy.
Thus % efficiency $=\frac{output}{input}\times 100$