5.20 As shown in Fig. P5.20, a reversible power cycle receives energy QH by heat transfer from a hot reservoir at TH and rejects energy QC by heat transfer to a cold reservoir at TC. (a) If TH=1200K and TC=300K, what is the thermal efficiency? (b) If TH=500C,TC=20C, and Wcycle=1000kJ, what are QH and QC, each in kJ ? (c) If =60% and TC=40F, what is TH, in F ? (d) If =40% and TH=727C, what is TC, in C ? Fig. P5.20