An electric fan rotates due to the interaction between an electric motor and magnetic fields. The motor converts electrical energy into mechanical energy, causing the fan blades to spin. When electricity flows through the motor's coils, it creates a magnetic field. This magnetic field interacts with permanent magnets or other magnetic components within the motor, generating rotational motion.

The process begins with the electric current passing through the motor's windings, which are coiled wires. These windings are made of copper, which is a good conductor of electricity. As the current flows through the windings, it generates a magnetic field around the wire. According to Faraday's law of electromagnetic induction, a changing magnetic field induces an electric current in a conductor. In this case, the changing magnetic field in the motor's windings induces an electric current in the fan's blades.

The fan's blades are attached to a shaft that is connected to the motor's rotor. As the magnetic fields generated by the motor's windings and the permanent magnets interact, they create a torque that causes the rotor to spin. This spinning motion is then transferred to the fan blades, which start to rotate, creating air movement.

The efficiency of an electric fan's rotation is influenced by various factors, including the design of the motor, the quality of the materials used, and the balance of the fan blades. For instance, a well-designed motor with high-quality materials and balanced blades will rotate more efficiently, resulting in better air circulation and less noise.

According to a study published in the Journal of Engineering for Gas Turbines and Power, the efficiency of an electric fan can range from 30% to 70%. This efficiency is determined by the motor's design and the fan's aerodynamic properties. A more efficient fan will consume less energy while providing the same amount of air movement as a less efficient fan.

In conclusion, an electric fan rotates due to the interaction between an electric motor and magnetic fields. This interaction generates torque, causing the fan blades to spin and create air movement. The efficiency of the rotation is influenced by various factors, including motor design and blade balance.