The internal energy of a substance

$A$ thermodynamic process $(B \rightarrow E)$ is shown in the graph below. The work done in this process is equal to the area under the curve. Identify the correct area representing the work done.

What will be the work done on an ideal gas enclosed in a cylinder,when it is compressed by a constant external pressure,$p_{ext}$ in a single step as shown in the figure? Explain graphically.

$A$ system goes from $A$ to $B$ via two processes $I$ and $II$ as shown in the figure. If $\Delta U_1$ and $\Delta U_2$ are the changes in internal energies in the processes $I$ and $II$ respectively,then:

Identify an example of an intensive property from the following:

The work done in an isothermal reversible process for an ideal gas is-