Refrigeration Cycles & Psychrometry question bank (Thermodynamics & Thermal Sciences)

[Refrigeration Cycles & Psychrometry Concept 4] A Carnot heat engine operates between source temperature $T_H = 800\text{ K}$ and sink temperature $T_L = 400\text{ K}$. It rejects $1200\text{ kJ}$ of heat to the sink. What is the net mechanical work output developed by the engine?

[Refrigeration Cycles & Psychrometry Concept 9] An ideal gas undergoes a reversible polytropic process $PV^n = C$. If the heat capacity ratio is $\gamma = C_p / C_v$, for what value of $n$ does the heat transfer during the process equal zero?