Question

A common motor is set up with a set of stationary magnets (called stators) and a rotating coil of wire (called a rotor)

In order to made the rotor move, the current through the wires has to keep changing. Which of the following is the best explanation for why this needs to happen?

a. The changing of the current requires a change in the strength of the field, so the motor will rotate faster due to the increased field
b. The changing of the current will cause the magnetic field effect of the stators to reduce over time, thus meaning the magnetic field of the rotor will overtake the stator field and move to compensate it
Selected:c. The changing of the current will force the rotor to move because the electrical current will require a changing coil in order to produce the magnetic fieldThis answer is incorrect.
d. The changing of the current reverses the polarity of the induced magnetic field, thus causing each stator to keep pushing the rotor due to repulsive forces

Answer 1

Option D.

Step-by-step explanation:

Here is how :

Basically, the changing of the current reverses the polarity of the induced magnetic field, thus causing each stator to keep pushing the rotor due to what so called as "repulsive forces".

In a motor, the interaction between the magnetic fields of the stators and the rotor creates a force that causes the rotor to rotate. By continuously changing the current in the rotor's coil, the polarity of the magnetic field produced by the rotor changes. This changing magnetic field interacts with the fixed stator magnets, resulting in a repulsive force that keeps pushing the rotor to rotate. This process of reversing the polarity of the induced magnetic field ensures continuous rotation of the motor.