1. A Steam Turbine Conceptual Physics Text Correlation: Section 24.5 49

3. Question 1 Why condense the steam after it turns the paddle? Why not redirect it to the boiler as hot as possible so less energy is needed to bring it to high- pressure steam again? Answer: That would be wonderful. But then the back pressure against the back side of the paddle would be greater and the paddle would turn less. If, for example, the back pressure were as great as the pressure of incoming steam, the paddle wouldn't turn at all.

4. Question 2 How does a temperature difference between source and sink affect efficiency? Answer: The torque that spins the turbine comes from the net force on the turbine blades -the" paddle wheels. " This is the difference between the force of high- pressure incoming steam and the force due to the back pressure of spent steam on the back side of the paddle wheel. The hotter the incoming steam, the greater the pressure it exerts, and the cooler the spent steam, the less pressure it exerts. Hence higher efficiency occurs for greater temperature differences between the source and the sink.