A gas in a piston-cylinder assembly undergoes a compression process for which the relation between pressure and volume is given by PVn = constant. The initial volume is 0.1 m3 , the final volume is 0.04 m3 , and the final pressure is 2 bar. Determine the initial pressure (bar), and the work for the process, in kJ, if (a) n = 0, (b) n = 1, (c) n = 1.3.

Explanation:

The given data is as follows.

  = 2 bar,     = ?

  ,    

We know that,

        = constant

or,    

(a)  For n = 0; we will calculate the initial pressure as follows.

              = 2 bar

(b)  For n = 1; we will calculate the initial pressure as follows.

              = 0.8 bar

(c) For n = 1.3; we will calculate the initial pressure as follows.

              = 2

            = 0.6

small = small current large mag large current