Question

Write the two laws of thermodynamics. Write the two laws in terms of the efficiency.

For the efficiency values chose from these options: higher or equal to 1 (efficiency ≥ 1), lower or equal to 1 (efficiency ≤ 1), higher than 1 (efficiency >1), or lower than 1 (efficiency <1). Explain.

Answer 1

The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another. For example, turning on a light would seem to produce energy. Heat given to the system is converted into its internal energy and the work done.

So work done by the system is given by this equation.

The efficiency of the system can be written as

where is the efficiency of the system.

Second Law efficiency is a measure of how much of the theoretical maximum (Carnot) you achieve, or in other words, a comparison of the system’s thermal efficiency to the maximum possible efficiency. The Second Law efficiency will always be between the Carnot and First Law

efficiencies.

Both of these laws gives the proof that efficiency of a system cannot be greater than equal to 1.

Kelvin-Planck statement says that when work is being performed, some amount of heat is rejected from high-temperature body to low-temperature body. So efficiency can not be equal to 1.