SOLVED:A heat engine cycle often used in refrigeration, is the Brayton cycle, which involves an adiabatic compression. followed by an isobaric expansion, an adiabatic expansion and finally an isobaric compression. The system begins at temperature T1 and transitions to temperatures T2, T3, and T4 after respective parts of the cycle. a) Sketch this cycle on a p V -diagram. b) Show that the efficiency of the overall cycle is given by ϵ=1-(TA-T1) /(T3-T2)