Question

Which law of thermodynamics helps in calculating the absolute entropies of various substances at different temperatures?
A.First law
B.Second law
C.Third law
D.Zeroth Law

Answer 1

The entropy of a substance is defined as that property that measures the randomness or the chaos in any substance. It is a physical property that is proportional to the quantity of energy that is no longer available to do physical work.

Complete answer:
Entropy is the physical quantity that measures the randomness of a system and its S.I. unit is equal to Joules per Kelvin. The second of thermodynamics states that the entropy of any system with increased levels of entropy is a stable system or the entropy of the universe always tends to increase. Hence the second law of thermodynamics helps in calculating the absolute entropies of various substances at different temperatures.

So, the correct answer is option B.

Note:
The first law of thermodynamics states that, the heat supplied to a system is spent in two ways, firstly to increase the internal energy of the system and secondly to perform external work. This law is also a direct consequence of the law of conservation of energy.
The third law of thermodynamics states that the entropy of a perfect crystal is equal to zero at absolute zero of temperature of $\text{0 Kelvin}$ temperature.
The zeroth law of thermodynamics states that, if the temperature of two bodies A and B are in thermal equilibrium with each other and if a third body C is also in thermal equilibrium with each other, then, A and C will also be in thermal equilibrium with each other.