Answer:
Windmills (wind turbines) are generally made up of 2-3 blades that are also considered as the propeller-like blades and this is fixed about the rotor at the top of a pillar or tower at a height of about 80-100 feet. This is because the wind is generally fast at about this height.
The rotor is again fixed to a major shaft, and when the prevailing wind is high enough in that area then the turbines rotate and due to this rotation, the generator within the major shaft starts spinning thereby produces the electricity. Thus they are one of the efficient ways of using wind energy.