For an isothermal irreversible expansion, Work done (W)=−pext(V2−V1) where, V1= initial volume V2= final volume Given, pext=105Nm−2, V1=10−3 m3, V2=10−2 m3 On substituting the given values in Eq, (i), We get, W=−105Nm−2(10−2 m3−10−3 m3)=−105Nm−2×10−3(10−1)m3=−900Nm=−900 J