Question

Hydroelectric power generation uses falling water as a source of energy to turn turbine blades and generate electrical power. In a power station, 1000 × 10³ kg water falls through a height of 51 m in one second.

 (i) Calculate the work done by the falling water? 

(ii) How much power can be generated under ideal conditions?

Answer 1

(i) The potential energy of the water at the top = mgh

Water loses all its potential energy. The same is converted into work in moving the turbine blades. Therefore

ii) The work done per second is given by

Ideal conditions mean that there is no loss of energy due to frictional forces. In practice, there is the always some loss in machines. Such losses can be minimized but can never be eliminated.