Final answer:
The stator is the part of an AC induction motor that creates the rotating magnetic field, essential for the operation of the motor.
Step-by-step explanation:
The part of an AC induction motor that creates the rotating magnetic field is called the stator. The stator is the stationary part of the motor's electromagnetic circuit and usually consists of either windings or permanent magnets that generate a rotating magnetic field. This magnetic field interacts with the rotor, which is the moving part of the motor, inducing an electromotive force (emf) that results in motion. The rotor turns because of the magnetic interaction with the rotating magnetic field produced by the stator. The other options listed, b) Rotor, c) Commutator, and d) Capacitor, have different functions in various types of motors. The commutator is used in DC motors to reverse the direction of current and maintain rotational motion, but is not a part of AC induction motors.
Motors turn electrical energy into mechanical work by applying a torque on loops of wire within a magnetic field. The changing magnetic field due to the rotation of the rotor generates what's known as back emf, which opposes the input emf in a motor. Both motors and electric generators utilize the principle of electromagnetic induction; however, while motors convert electrical energy to mechanical energy, generators do the opposite.