Question

In a hydroelectric power plant, water falls at a rate of 1000 $\frac{kg}{s}$ from a height of 100m. Assuming that 50% of the energy of falling water is converted into electrical energy, calculate the power generated per second.

• A. 500000 W
• B. 495000 W
• C. 490000 W
• D. 480000 W

Answer 1

The correct option is C

490000 W

Mass of water = 1000 kg

Height = 100m

Energy possessed by water = Potential energy = m $\times$ g $\times$ h = 1000 $\times$ 9.8 $\times$ 100 = 980000J

It is mentioned that only 50% of the energy is converted into electrical energy.

So, the amount of Electrical energy generated = Total $\times$ $\frac{50}{100}$ = 490000J

Time taken is 1 second, we know that the power generated =$\frac{energy}{time}$ = 490000 W.