Imagine a carnot engine that operates between the temperaturesTh=850K & TI=300K.

Question

Imagine a carnot engine that operates between the temperaturesTh=850K & TI=300K. The engine performs 1200J of work eachcycle, which takes 0.25s.
(a) What is the efficiency of this engine?
(b) What is the average power of this engine?
(c) How much energy Qh is extracted as heat from the hightemperature reservoir every     cycle?
(d) How much energy QI is delivered as heat to the low temperaturereservoir every cycle?
(e) By how much does the entrophy of working substance change as aresult of the energy transferred to it from the high temperaturereservoir? From it to the low temperature reservoir?

Explanation / Answer

a) We know the formula for the efficiency of the carnot's engineis                        e = 1 - (Tl / Th)                           = 1 - (300K / 850K)                           = 0.647 = 64.7% b) We know that power (P) = W / t                                       = (1200J) / (0.25s) c) We know that e = W / Qh                      Qh = W / e                            = (1200J) / (0.647)                             =1854.55 J d) And W = Qh - Ql          Ql= Qh - W = 1854.55 J - 1200J = 654.55 J          Ql= Qh - W = 1854.55 J - 1200J = 654.55 J

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