Question 8: A new heat engine cycle can be described by an adiabatic compression (a - b), an isothermal expansion (b - c), and an isochoric cooling process (c - a), as shown in the graph. The compression ratio is r. For a diatomic ideal gas: Cv = 5R/2, Cp = 7R/2, y = 1.4 Assume the processes are reversible. a) Write down the expressions (not the values) for the heat transferred during each process. Pressure a Vo r Vo Volume b) Find an expression for the efficiency of this cycle in terms of only the compression ratio. c) If state a is at room temperature (300 K) and atmospheric pressure (100 kPa), and the compression ratio is 4, what is the efficiency for this heat engine? d) How does your answer in (c) compare to the efficiency that a Carnot engine running between the same two temperatures would have? (e) What is the entropy change for each process if V. is 1L, and, as above, state a is at room temperature (300 K) and atmospheric pressure (100 kPa)? f) The isochoric cooling process, c- a, occurs because the gas is brought into contact with an isothermal cold reservoir at temperature Told = 300K. What is the entropy change of this reservoir during the process c - a