Chemical Engineering - Chemical Engineering Thermodynamics - Discussion

The graph under the PV diagram for closed system gives the work. In the expansion region the graph of isotherm is above the graph of adiabatic curve, as the slope of adiabatic curve (gamma) is greater than that of isotherm curve. So the area under the isotherm is larger.

Isothermal is the correct answer.

Only isothermal process exists in this question due to expansion process of a gas over a given pressure.

Answer should be A.

As we know that, the here expansion process is occurring. And also it is a closed process. So from graph of P-V you can see the maximum area covered is by ISOTHERMAL LINE.

Understand this problem is to see the P-V graph of Carnot cycle. Work done in any process will follow.

dW = p.dV.

It means if we plot a graph between pressure and volume of the gas then area covered under the curve followed by a process will show the work done.

Now, see the Carnot cycle and slopes of adiabatic and isothermal processes. There you can see that isothermal process will be covering more area than adiabatic process. And hence work done will be more in an isothermal process.

dU = Q+W.

For T = K, dU = CvdT = 0.

-Q = W , hence heat input equals work output.

Why not adiabatic?

Please explain me.

The PV graph of isothermal process cover max area as compare to adaibatic and isentropic process in expansion of gas that's why max work secured in isothermal process.

Hence option A is right.

Can anyone explain it more clearly?

According to given statement, the relation showed between volume and pressure not a temperature means T=constant, therefore it is ISO thermal Condition.