Question

The diagram shows a PV graph of a thermodynamic behavious of an ideal gas. Find out from this graph (i) work done in the process `AtoB,BtoC,CtoD and DtoA`, (ii) work done in the complete cycle
`AtoBtoCtoDtoA`.

Answer 1

(i) Work done in the process `AtoB` (the process is expansion, hence work is done by the gas)
`=-PxxdV=-12xx10^(5)xx5xx10^(-3)`
`=-6000J`
Work done in the process `BtoC` is zero as volume remains constant.
Work done in the process `CtoD` (the process is concentration, hence work is done on the gas)
`=PxxdV=2xx10^(5)xx5xx10^(-3)`
`=PxxdV=2xx10^(5)xx5xx10^(-3)`
`=1000J`
(ii) Work done in the process `DtoA` is zero as vlume remains constant.
Net ork done in the whole cycle `=-6000+1000=-5000J`
i.e., net work is done by the gas.