Question

A steam turbine operates at a boiler temperature of 450K and an exhaust temperature of 300K. What is the maximum theoritical efficiency of this system?
(A) 0.240
(B) 0.500
(C) 0.333
(D) 0.600

Answer 1

For any cycle operating between two temperatures, none can exceed the efficiency of a Carnot cycle. So the maximal theoretical efficiency will be equal to efficiency of the Carnot cycle with temperatures 450K and 300K.

The efficiency is

$\eta_{\text{max}} = 1 - \dfrac{T_c}{T_h} = 1 - \dfrac{300}{450} = 0.333.$

So the answer is C.