Answer
(a) $Q_H = 6500 J$
(b) $\epsilon = 33.8 \%$
Work Step by Step
(a) $Q_H = W + |Q_C|$
$Q_H = 2200 J + 4300 J$
$Q_H = 6500 J$
(b) Thermal efficiency,
$\epsilon = \frac{W}{|Q_H|} $
$\epsilon = \frac{2200 J }{6500 J} \times 100 $
$\epsilon = 33.8 \%$
