The data listed below are claimed for a power cycle operating between hot and cold reservoirs at 1500 K and 450 K, respectively. For each case, determine whether the cycle operates reversibly, operates irreversibly, or is impossible.
a) QH=600 kJ, W(cycle)=300 kJ, QC=300 kJ
b) QH=400 kJ, W(cycle)=280 kJ, QC=120 kJ
c) QH=700 kJ, W(cycle)=300 kJ, QC=500 kJ
d) QH=800 kJ, W(cycle)=600 kJ, QC=200 kJ