Question

A wind turbine takes in energy from wind with the goal of converting it into electrical energy. Much of the wind energy is also converted into the kinetic energy of the spinning turbine and heat lost to the air around it.

An illustration of a windmill with a wide arrow away from it labeled kinetic energy of wind 3000 J and it separates into 3 different arrows, one labeled electric energy 750 J, the second labeled heat 750 J and the third which is the widest labeled kinetic energy of turbine blank J.
If the goal of the turbine is to put out electric energy, what is the efficiency of the turbine?

25%
50%
75%
100%

Answer 1

Efficiency = useful output / input = 750 J / 3000 J = 0.25 = 25%.

Answer: 25%