Question

A hydroelectric power station take sits water from a lake whose water level is at a height of 50 m above the turbine. Assuming an overall efficiency of 40%, calculate the mass of water which must flow through the turbine each second to produce a power output of 1 MW.(Take g=10 m$s^{-2}$).

Answer 1

Since effieciency is 40 %

Useful energy = 40% mgh

$=\frac{40}{100}\times m\times 10\times 50$

1MW = 200m

1000000 = 200m

m = $\frac{1000000}{200}$= 5000kg