State third law of thermodynamics. What is its usefulness?
Answers
Answered by
4
Third law of thermodynamics states that entropy of a perfect crystalline substance is zero at absolute zero (0 K) temperature. That is entropy of any substance is least when it is a perfect crystal at absolute zero. With increase in temperature the disorderness of molecules increases and thus at temperatures above 0 K entropy of any substance is greater than zero.
Some of important applications are:
1) This law provides the bases for 1st and 2nd law i.e we can calculate absolute entropies and chemical affinity of substance(for chemists).
But in engineering we have nothing to do with absolute values since we always deals with change in property.
2) As perfect substance goes to ordered state there is decrease in entropy so its temp decreases and hence theoretically there can be 0kelvin.
A) This concept is utilised in adiabatic cooling(cryogenics), where in each cycle by external magnetic field spin states of ferromagnetic material is lowered into ordered one and by this magnetic cooling we have now attained 20nK. This magnetic cooling is also known as green refrigeration which is pollution free, which can replace existing conventional Vapour compression system.
B) Spin ice: A type of crystal with ions placed in a tetrahedral shape and temp. Alteration can change their spin state such that they behave like magnetic monopole. At absolute temp, spin states disappairs i.e.; perfect arrangement. So altering spin state by straining we can boost up memory storage devices that have gaint storage capacity than existing one.
So at absolute zero any perfect substance have to come to its ordered state.
Hope this will help you..... ✌
Some of important applications are:
1) This law provides the bases for 1st and 2nd law i.e we can calculate absolute entropies and chemical affinity of substance(for chemists).
But in engineering we have nothing to do with absolute values since we always deals with change in property.
2) As perfect substance goes to ordered state there is decrease in entropy so its temp decreases and hence theoretically there can be 0kelvin.
A) This concept is utilised in adiabatic cooling(cryogenics), where in each cycle by external magnetic field spin states of ferromagnetic material is lowered into ordered one and by this magnetic cooling we have now attained 20nK. This magnetic cooling is also known as green refrigeration which is pollution free, which can replace existing conventional Vapour compression system.
B) Spin ice: A type of crystal with ions placed in a tetrahedral shape and temp. Alteration can change their spin state such that they behave like magnetic monopole. At absolute temp, spin states disappairs i.e.; perfect arrangement. So altering spin state by straining we can boost up memory storage devices that have gaint storage capacity than existing one.
So at absolute zero any perfect substance have to come to its ordered state.
Hope this will help you..... ✌
Answered by
0
Explanation:
The entropy of a system approaches a constant value as its temperature approaches absolute zero.
The third law of thermodynamics is sometime state as above mentioned
Similar questions