A mixture of gases contains $4$ moles of oxygen and $2$ moles of argon at absolute temperature $T.$ The total internal energy of this system (neglecting vibrations) is $[R=$ universal gas constant ]

Figure shows $P~T$ diagram for $2$ moles of an ideal gas. The volume of the gas is nearly

The $P~V$ curve for $1$ mole of an ideal monoatomic gas during process $A\to B$ is shown in figure. The change in internal energy of the gas is

In the process shown by the graph the change in internal energy is $\Delta U,$ work done by the gas is $W$ and heat absorbed by the gas is $Q.$ Select the correct alternatives.