(Ist law of thermodynamics) \(\Rightarrow \Delta \mathrm{Q}=\Delta \mathrm{u}+\mathrm{P} \Delta \mathrm{v}\)
or \(150=\Delta u+100(1-2)\)
\(=\Delta u-100\)
\(\therefore \Delta u=150+100=250 \mathrm{J}\)
Thus the internal energy of the gas increases by \(250 \mathrm{J}\)