What is the total work done in a cyclic process ?

When a system is taken from a state $i$ to $f$ along the path $iaf$ (as shown in the figure). $Q = 50\, cal$ and $W = 20\, cal$ ; along path $ibf,$ $Q = 36\, cal.$

$(i)$ What is $W$ along path $ibf$ ?

$(ii)$ If $W = 13$ cal for path $fi$, what is $Q$ for the path $fi$ ?

$(iii)$ Take $E_{int,i} = 10\,\, cal$ then what is $E_{int,f}$ ?

A given mass of a gas expands from a state $A$ to the state $B$ by three paths $1, 2$ and $3$ as shown in $T-V$ indicator diagram. If $W_1, W_2$ and $W_3$ respectively be the work done by the gas along the three paths, then

A thermodynamic system is taken from state $A$ to $B$ along $ACB$ and is brought back to $A$ along $BDA$ as shown in the $PV$ diagram. The net work done during the complete cycle is given by the area

If one mole of an ideal gas at $\left( P _{1}, V _{1}\right)$ is allowed to expand reversibly and isothermally ($A$ to $B$ ) its pressure is reduced to one-half of the original pressure (see $figure$). This is followed by a constant volume cooling till its pressure is reduced to one-fourth of the initial value $( B \rightarrow C ) .$ Then it is restored to its initial state by a reversible adiabatic compression ($C$ to $A$). The net workdone by the gas is equal to  …… .