ISRO 2018 Refrigeration and Air-Conditioning Questions, Answers and Explanation 1 . Carnot cycle consists of a) Two constant pressure and two isentropic processes b) One constant isenthalpic, one constant volume and two constant pressure processes c) Two isothermal and two isentropic processes d) One constant pressure, one constant volume and two isothermal processes. Answer c) Two isothermal and two isentropic processes Explanation [ Thermal Engineering ] The most efficient heat engine cycle is the Carnot Engine cycle and it is represented as a rectangle in T-S diagram Otto Cycle - 2 constant volume and 2 isentropic Diesel Cycle - 1 constant pressure, 1 constant volume and 2 isentropic 2. One reversible heat engine operates between 1600K and T 2 K and another reversible heat engine operates between T 2 K and 400K. If both engines have the same heat input and output, then the temperature T 2 is equal to a) 800K b) 1600K c) 1200K d) 6400K...