In a pumped-storage hydroelectric power station, water flows from a high-altitude reservoir down through a steel pipe (penstock) to drive a turbine generator. Engineers coat the inner surface of the penstock with a specialized, low-drag hydrophobic polymer lining.
Explain how this polymer lining improves the efficiency of the hydroelectric power generation system.
38 exam-style questions on Edexcel GCSE Physics 3.2 Dissipation and efficiency. Each one has a worked solution and a mark scheme showing where the marks go.