Question

To work properly, wind -electric generators need wind speeds of at least about

Answer 1

15 km/ hr option b u can see in ncert

Answer 2

Correct Answer is Option B--15km/hr

Wind energy is the renewable source of energy which uses wind turbines.
Wind turbines converts the kinetic energy in the wind into mechanical power.
This mechanical power which is produced can be used to perform various tasks.

The wind speed is the one of the importance factor which influences the amount of energy wind turbine can produce.A relative and consistent wind flow is required for effective working of wind speed.

For efficient wind energy system we require an average annual wind speed of at least 15km/hr.