InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Water is pumped out of a well 10m deep by means of a pump rated at 10 kW. Find the efficiency of the motor if 4200 kg of water is pumped out every minute. Take `g = 10m//s^2.` |
|
Answer» Work done by the pump per minute, `W =mgh = (4200) (10 (10)) = 4.2 xx 10^5 J` Output power of the pump `= (W)/(t) = (4.2xx 10^5J)/(60s) = 7 xx 10^3 W = 7kW` Efficiency of the pump `= ("output power")/("input power" (i.e. "rated power")) = (7kW)/(10kW) = 0.7 = 70%` |
|