12.44: A monatomic ideal ga
u,qpoiozggq(91z 0 5es is the working substance for a refrigerator that undergoes the cyclic process (ABCDA) shown in the PV diagram. The processes are all isoch
goe0z(5 i o91qzg,qpuoric or isobaric with pressures between $P_0$ and $2P_0$ and volumes between $V_0$ and 2$V_0$ . What is the coefficient of performance for this refrigerator?