Answer:
Efficiency is ratio of output energy and input energy

Step-by-step explanation:
Efficiency is defined as the output that we will get from a given machine for a given input of energy.
So here we know that input energy that we are getting from wind is in the form of electrical energy converted by the turbine and the input energy here is in the form of kinetic energy of wind or air molecules
so here this kinetic energy of wind will help to rotate the turbine due to which we will get the output electrical energy but in this whole process some of the wind energy is converted into heat due to frictional force between several components of turbine which shows our energy loss in this process
so efficiency is given by
