$(1)$ \[ \begin{align} \eta = 1- \frac{293}{1073} &=0.72693 \\ &=72.69 \% \end{align} \] $(2)$ \[ \eta = \frac{P}{Q_1}より \\ \begin{align} P = \eta Q_1 &=0.72693 \times 2\,\rm{kW} \\ &=1.4538 \\ &=1.454 \, \rm{kW} \end{align} \]