$A$ thermodynamic system is taken through the cyclic process $ABC$ as shown in the figure ($P-V$ graph: $A(2, 100)$, $B(5, 300)$, $C(5, 100)$). The total work done by the system during the cycle $ABC$ is . . . . . . $J$.

For one complete cycle of a thermodynamic process on a gas as shown in the $P-V$ diagram,which of the following is true?

$A$ thermodynamic process is shown in the figure. The pressures and volumes corresponding to some points in the figure are:
$P_A = 3 \times 10^4 \, Pa, \, P_B = 8 \times 10^4 \, Pa$ and $V_A = 2 \times 10^{-3} \, m^3, \, V_D = 5 \times 10^{-3} \, m^3$
In process $AB$,$600 \, J$ of heat is added to the system and in process $BC$,$200 \, J$ of heat is added to the system. The change in internal energy of the system in process $AC$ would be ...... $J$.

The work done by a gas as it is taken in a cyclic process (shown in the graph) is (in $PV$)

In a thermodynamic process,the pressures and volumes corresponding to some points in the figure are $P_A = 3 \times 10^4 \, Pa$,$V_A = 2 \times 10^{-3} \, m^3$,$P_B = 8 \times 10^4 \, Pa$,and $V_D = 5 \times 10^{-3} \, m^3$. In process $AB$,$600 \, J$ of heat is added,and in process $BC$,$200 \, J$ of heat is added to the system. The change in the internal energy in process $AC$ would be .... $J$.

An ideal gas undergoes the cyclic process $abca$ as shown in the given $P-V$ diagram. It rejects $50 \,J$ of heat during $ab$ and absorbs $80 \,J$ of heat during $ca$. During $bc$, there is no transfer of heat and $40 \,J$ of work is done by the gas. What should be the area of the closed curve $abca$ (in $\,J$)?