Answer:

Step-by-step explanation:
Given:
- width of the stream,

- depth of the stream,

- height of the waterfall,

- velocity of flow,

- efficiency promised by the manufacturer,

Now the volume flow rate of the water through the fall:



Now we know the density of water is 1000 kilogram per cubic meter.
So, the mass flow rate:



Hence potential energy delivered to the system per second:



Now the power generated according to efficiency:


