Three moles of an ideal gas are taken through a cyclic process ABCA as shown on T − V diagram in Fig.
The gas loses 2510 J of heat in the complete cycle. If , The work done by the gas
during the process BC is
5000 J
−5000 J
4000 J
−2500 J
In process AB, the volume V increases linearly with temperature T. Hence process AB is
isobaric (constant pressure). Therefore, work done in this process is
Process CA is isochoric (constant volume). Hence work done in this process Since the whole process ABCA is cyclic, the change in internal energy in the complete cycle is zero, i.e.
. Now, from the first law of thermodynamics, (Given Q =
−2510J)
The negative sign shows that the work is done by the gas