what is responsible for making an axle spin in an electric motor?\no an outside power source attached to a…

Brief Explanations:

An electric motor operates based on the principle of electromagnetism. When an electric current passes through an armature (a coil of wire) that is placed in a magnetic field, a force is exerted on the armature due to the interaction between the current - carrying conductor and the magnetic field. This force causes the armature (and thus the axle to which it is attached) to rotate.

• Option 1: An outside power source attached to a magnet does not explain the rotation mechanism. The key is the interaction of current and magnetic field in the motor's working part (armature).
• Option 2: An outside power source attached directly to the axle is not how an electric motor works. Electric motors use electromagnetic forces, not a simple direct - mechanical connection from an external power source to the axle.
• Option 4: A magnetic field inducing a current in an armature that lies in a magnetic field is more related to the principle of a generator (Faraday's law of electromagnetic induction, where a changing magnetic field induces a current). In a motor, we supply a current (not induce it in the armature in the basic operation sense) to get rotation.

Answer:

an electric current passing through an armature that lies in a magnetic field