Which of the following statements about wind energy is not true?
a. wind energy is a nonrenewable energy resource.
b. wind energy is used to sail ships.
c. wind energy is not reliable.
d. windmills are currently being used to provide energy.

The correct option is (a).

Explanation:

Windmills: In wind mill, the kinetic energy from the moving air is converted into electricity by wind turbines.

Wind energy is a renewable source of the energy. It is inexhaustible source of the energy.

Wind energy is used to sail ships.

It is unlimited. It is non polluting way to generate electricity.

The wind mills are mostly located in the coastal area. They are currently being used to provide energy.

But it is unreliable source of energy. If the wind blowing then the wind energy cannot be converted into electrical energy by using wind turbines in the case of windmills.

Wind is necessary to generate wind energy.

Therefore, the correct options (a).

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia