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Physics · WORK, ENERGY AND POWER
हिन्दीAn electric pump is used to fill a water tank of capacity \( 30\text{ m}^3 \) located at a height of \( 40\text{ m} \) above the ground in \( 15\text{ minutes} \). If the overall efficiency of the pump is \( 30\% \) and \( g = 9.8\text{ m s}^{-2} \), the electrical power consumed by the pump is:
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Correct answer · Option A
\( 43.56\text{ kW} \)
Explanation
Output work \( W = mgh = (30 \times 10^3) \times 9.8 \times 40 = 1.176 \times 10^7\text{ J} \). Output power \( P_{\text{out}} = \frac{1.176 \times 10^7}{15 \times 60} = 13066.7\text{ W} = 13.07\text{ kW} \). Input power \( P_{\text{in}} = \frac{P_{\text{out}}}{\eta} = \frac{13.067}{0.30} \approx 43.56\text{ kW} \).
