Observe the given picture and answer the questions.[Picture: a tall tower carrying a set of long blades at the top; the blades are shown turning, their shaft passes through a gear box to a generator mounted behind them, and the whole unit turns on th…

Answer: (a) Wind mill (wind turbine) used for generating electricity. (b) Wind. (c) Because it is renewable and causes no pollution.

(a) The picture shows a wind mill in which the kinetic energy of moving air turns the blades; the shaft, gear box and generator convert this into electrical energy.

(b) The source of energy is the wind, i.e. the kinetic energy of moving air, which itself is produced by the heating of the earth’s surface by the sun.

(c) No fuel is burnt, so no smoke, ash, CO₂ or SO₂ is produced; wind is available free of cost and is never exhausted, and the land below the wind mill can still be used for farming. Hence it is eco-friendly.