University Physics Volume 2

# Key Equations

### Key Equations

 Result of energy conservation $W=Qh−QcW=Qh−Qc$ Efficiency of a heat engine $e=WQh=1−QcQhe=WQh=1−QcQh$ Coefficient of performance of a refrigerator $KR=QcW=QcQh−QcKR=QcW=QcQh−Qc$ Coefficient of performance of a heat pump $KP=QhW=QhQh−QcKP=QhW=QhQh−Qc$ Resulting efficiency of a Carnot cycle $e=1−TcThe=1−TcTh$ Performance coefficient of a reversible refrigerator $KR=TcTh−TcKR=TcTh−Tc$ Performance coefficient of a reversible heat pump $KP=ThTh−TcKP=ThTh−Tc$ Entropy of a system undergoing a reversible process at a constant temperature $ΔS=QTΔS=QT$ Change of entropy of a system under a reversible process $ΔS=SB−SA=∫ABdQ/TΔS=SB−SA=∫ABdQ/T$ Entropy of a system undergoing any complete reversible cyclic process $∮dS=∮dQT=0∮dS=∮dQT=0$ Change of entropy of a closed system under an irreversible process $ΔS≥0ΔS≥0$ Change in entropy of the system along an isotherm $limT→0(ΔS)T=0limT→0(ΔS)T=0$