ECONOMICS (CBSE/UGC NET)

Detailed explanation-1: -Turbine blades vary in size, but a typical modern land-based wind turbine has blades of over 170 feet (52 meters). The largest turbine is GE’s Haliade-X offshore wind turbine, with blades 351 feet long (107 meters) – about the same length as a football field.

Detailed explanation-2: -With two blades you need significantly less material, construction and maintenance costs. A third or fourth rotor blade makes the wind turbine marginally more efficient, while the construction and material costs increase considerably. The four blades of our historic wind mills were more of a practical choice.

Detailed explanation-3: -This is because their angular momentum in the vertical axis changes depending on whether the blades are vertical or horizontal. With three blades, the angular momentum stays constant because when one blade is up, the other two are pointing at an angle. So the turbine can rotate into the wind smoothly.

Detailed explanation-4: -9. Name the windmill which has four blades mounted on a central post. Explanation: The post mill has blades mounted on a central post.