JEE Main Physics question
Water falls from a height of 60 m at the rate of 15 kg/s to operate a turbine. The losses due to frictional forces are 10% of energy. How much power is generated by the turbine? (g = 10 m/s²)
Answer: (C)
Solution
Power input = (dm/dt)gh = 15 × 10 × 60 = 9000 W = 9 kW. With 10% lost to friction, power output = 90% of 9 kW = 8.1 kW.