Q 11-05-010NEETNEET 2021Top questionEasy
Water falls from a height of $60$ m at the rate of $15$ kg/s to operate a turbine. The losses due to frictional force are $10\%$ of the input energy. How much power is generated by the turbine ? ($g = 10\ \text{m/s}^2$)
Answer: (C) $8.1$ kW
Concept. Input power $= \dfrac{dm}{dt}gh$; output is $90\%$ of it.
Step 1. Input. $15 \times 10 \times 60 = 9000$ W.
Step 2. Output. $0.9 \times 9000 = 8.1$ kW.
Answer. $8.1$ kW (Option C).
Solution by Sreeraj P, M.Sc Physics