THE LAWS OF THERMODYNAMICS

 

Thermodynamics is the branch of physics dealing with heat and temperature and their relation to energy and work. It deals with the behavior of systems that are in thermal equilibrium or approaching it,and provides the laws that govern the direction and magnitude of heat transfer.

1st Law of Thermodynamics The total energy of a closed system remains constant, although energy can be transformed from one form to another. It is expressed as ΔU = Q - W, where ΔU is the change in internal energy, Q is heat added to the system, and W is work done by the system.

2nd Law of Thermodynamics

The entropy of a closed system will always increase over time, leading to thermal equilibrium. It is stated as "Heat flows spontaneously from hot to cold." It is expressed as ΔS ≥ Q/T, where ΔS is the change in entropy, Q is heat, and T is temperature.

3rd Law of Thermodynamics

As the temperature of a system approaches absolute zero, its entropy approaches a minimum value. At absolute zero, a perfect crystal will have zero entropy.

Zeroth law of Thermodynamics

If body A and B are in equilibrium with each other and body B and C are in equilibrium with each other then body A and C will be in equilibrium with each other.