(lb). For a closed system containing ideal gas, the boundary work can be calculated by W_{b}=P_{1} Y_{1} \ln \left(\frac{V_{2}}{V_{1}}\right)=P_{2} V_{2} \ln \left(\frac{V_{2}}{V_{1}}\right) \text { for } (A) Isothermal (constant temperature)

process defined by PV=Const.;%3D (B) Constant pressure process; C) Constant volume process; (D) Polytropic process defined by PV* =Const.;