Experiments Involving Cyclic Processes

In the experiment of utilizing heat and work to acquire equivalent effects, the initial and final states of the system were dissimilar. The outcomes from such experiments are enough to form the foundation for the First Law. The modern formulation, though, is better introduced by considering a second kind of experiment, also carried out by Joule, in which heat and work are caused to open each other’s effects instead of to reproduce them. In this situation, a cyclic procedure is stated as follows:

“The procedure is cyclic when the initial and final states of the system executing the procedure are the same”.

In a cyclic process, all the system properties have similar values at the end of the procedure as at the starting.

There are at least two purposes for studying cyclic processes in looking for important relationships among temperature, work and heat:

• Cycles are general and significant in looking conversion, and they operate constantly.

• Since the system returns to its initial state, in a cyclic procedure it is not essential to thought the adjust spacing among ‘the’ and ‘equations’ equations of state of the functioning substances.

Coming back to the pair of procedures performed by Joule assumes the adiabatic stirring process of the figure (b) shown below be carried out first, resultant in an increase in water temperature. The stirring is then stopped, and the water in the vessel is brought into communication with and other body that is selected to be at a lower temperature than the water. The heat transfer in this situation is from the water, not to it, as an outcome of which the temperature of the water falls. The thermal communication among the water in the vessel and the cold body is broken as soon as the water temperature has fallen to the real value existing at the commencement of the stirring procedure. Under such circumstances, the water is in exactly similar state at the end as at the starting of the procedure. Therefore, the stirring and cooling of the water including the system altogether form a cyclic process.

The Joule and other orkers have carry out many cyclic experiments. Both the nature of the system and the nature of the procedures were differed. In each cyclic experiment, the sum outcomes of such experiments might be written symbolically as:

stands for ‘sum of all the work or heat communications throughout the cycle’. The proportionality constant J has similar value as in the primary set of experiments.