In a reversible isothermal process,the change in internal energy is

An ideal gas undergoes a cyclic transformation starting from the point $A$ and coming back to the same point by tracing the path $A$ $\rightarrow B$ $\rightarrow C$ $\rightarrow D$ $\rightarrow A$ as shown in the three cases above. Choose the correct option regarding $\Delta U$.

Expansion of a gas in vacuum is called free expansion. Calculate the work done and the change in internal energy when $1 \ L$ of ideal gas expands isothermally into vacuum until its total volume is $5 \ L$?

What are extensive properties?

Which one among the following is the correct option for the relationship between $C_{P}$ and $C_{V}$ for one mole of an ideal gas?

If $\Delta H$ is the change in enthalpy,$\Delta U$ is the change in internal energy,$N_P$ is the number of moles of products,and $N_r$ is the number of moles of reactants,then which of the following is correct for a gaseous reaction?