Question

Which of the following quantities is zero over one complete cycle in a cyclical process?

Answer 1

Cyclic process:
When a system returns to its original state after completing a series of changes, then it is known that a cycle is completed. This process is known as cyclic process. In a cyclic process the initial and the final state is same. As the internal energy U of the system depends only on the state of the system so in a cyclic process the net change of internal energy ∆U will be equal to zero i.e. ∆U = 0. Hence from the first law:

∆U = 0 = q + w
Hence, q = – w

If the process is taking place at constant temperature then the cycle is known as isothermal cycle. If the process is taking place reversibly then cycle is known as reversible cycle.

Example of the cyclic process:
The Carnot cycle is the best example of the cyclic process which is explained below:

The Carnot cycle:
The cycle was first discovered by a French engineer Sadi Carnot in 1824 which works on reversible cycle and is known as Carnot cycle.
Carnot employed a reversible cycle to demonstrate the maximum convertibility of heat into work. any fluid can be used to operate the Carnot cycle which is performed in an engine cylinder the head of which is suppose alternatively to be perfect conductor or a perfect insulator of the heat