
$P = \frac{{ - {P_0}}}{{{V_0}}}V + 3P$
$[slope = \frac{{ - {P_0}}}{{{V_0}}},c = 3{P_0}]$
$P{V_0} + {P_0}V = 3{P_0}{V_0}\,\,\,\,\,\,\,\,\,\,\,...\left( i \right)$
$But\,\,\,\,\,\,\,PV = nRT\,$
$\therefore P = \frac{{nRT}}{V}\,\,\,\,\,\,\,\,\,\,\,\,\,\,...\left( {ii} \right)$
$From\left( i \right)\& \left( {ii} \right)\frac{{nRT}}{V}{V_0} + {P_0}V = 3{P_0}{V_0}$
$\therefore nRT{V_0} + {P_0}{V^2} = 3{P_0}{V_0}$
$...\left( {iii} \right)$
For temperature to be maximum $\frac{{dT}}{{dV}} = 0$
Differentiating $e.q.(iii)\,by\,'v'\,we\,get$
$nR{V_0}\frac{{dT}}{{dV}} + {P_0}\left( {2v} \right) = 3{P_0}{V_0}$
$\therefore nR{V_0}\frac{{dT}}{{dV}} = 3{P_0}{V_0} - 2{P_0}V$
$\frac{{dT}}{{dV}} = \frac{{3{P_0}{V_0} - 2{P_0}V}}{{nR{V_0}}} = 0$
$V = \frac{{3{V_0}}}{2}\,\,\,\,\,\,\,\,\,\therefore P = \frac{{3{P_0}}}{2}$ $[From (i)]$
$\therefore \,{T_{\max }} = \frac{{9{P_0}{V_0}}}{{4nR}}\,\,\left[ {From\,\left( {iii} \right)} \right]$
$A \rightarrow B :$ Isothermal expansion at temperature $T$ so that the volume is doubled from $V _{1}$ to $V _{2}=2 V _{1}$ and pressure changes from $P _{1}$ to $P _{2}$
$B \rightarrow C :$ Isobaric compression at pressure $P _{2}$ to initial volume $V _{1}$
$C \rightarrow A$ : Isochoric change leading to change of pressure from $P _{2}$ to $P _{1}$
Total workdone in the complete cycle $ABCA$ is

$(i)$ Sequentially keeping in contact with $2$ reservoirs such that each reservoir supplies same amount of heat.
$(ii)$ Sequentially keeping in contact with $8$ reservoirs such that each reservoir supplies same amount of heat.
In both the cases body is brought from initial temperature $100^o C$ to final temperature $200^o C$. Entropy change of the body in the two cases respectively is :