What happens to the magnetic polarity in an AC motor?

In an AC motor, the magnetic polarity changes direction with the alternating current. This is a fundamental characteristic of alternating current, where the flow of electricity periodically reverses direction. As the current alternates, the magnetic field produced by the motor's windings also reverses its polarity. This continuous change is essential for the operation of an AC motor, as it allows for the rotation of the rotor. The alternating magnetic field interacts with the rotor in such a way that it creates torque, which is what drives the motor's movement. This dynamic behavior is crucial for the functioning of various applications where AC motors are utilized.

Other options suggest a static or unchanging nature of magnetic polarity, which does not accurately reflect the behavior of AC motors. A fixed magnetic polarity would lead to a lack of rotational movement, which is contrary to the operational principle of these motors. Similarly, fluctuating polarity only during startup does not account for the overall continuous operation of the motor while under load.