6. An engineer decides to exploit heat transfer between a hot temperature reservoir of 1200 C and a cold temperature reservoir of 30 C to make a heat engine. If heat is supplied to the heat engine at a rate of 200 kW: (a) What is the maximum power output of the heat engine? (4 marks) (b) Explain whether the power output of the heat engine will change if the temperature of the cold reservoir is reduced, with no other changes. (2 marks)