Consider a heat engine as shown in Fig. 12.7. Q1 and Q2 are heat added to heat bath T1 and heat taken from T2 in one cycle of engine. W is the mechanical work done on the engine.
If W > 0, then possibilities are:
(a) Q1 > Q2 > 0
(b) Q2 > Q1 > 0
(c) Q2 < Q1 < 0
(d) Q1 < 0, Q2 > 0