An electric pump extracts 3000 litres of water from a well 15 m deep in 5 minutes. The useful power of the pump is : (Take g = 10 m/s ^2 and density of water = 1000 kg/m ^3 )

Step-by-step solution

Volume of water, V = 3000 litres = 3 m ^3 Mass of water, m = V = 3 1000 = 3000 kg Work done in lifting water, W = mgh = 3000 10 15 = 450000 J Time taken, t = 5 minutes = 300 s Useful power, P = W t = 450000 300 = 1500 W = 1.5 kW Answer: 1.5 kW