Why do magnetic fields induce current in wires when the electrons in the wires aren't moving?

Question

I heard that magnetic fields are only have a force on electrons if they are moving in the fields. But changing magnetic fields are able to induce currents in wires even though the electrons in the wire aren't moving. I was wondering why this occurs. Also, do magnetic fields only induce current in loops of wire?

Answer 1

I heard that magnetic fields are only have a force on electrons if they are moving in the fields.

The effect of a magnetic field on moving electrons is a deflection rather than a (straight) movement. This is called the Hall effect or Lorentz force.

But changing magnetic fields are able to induce currents in wires even though the electrons in the wire aren't moving.

This is how a generator works. A changing magnetic field causes electrons to move in a conductor and it is the second possibility of electromagnetic induction processes. (The third phenomenon is the induction of a magnetic field by a current with the forced lateral deflection of the electrons. This is then a magnetic coil or the primary coil of a transformer works in the same way).

I was wondering why this occurs. Why (how) do magnetic fields induce current in wires when the electrons in the wires aren't moving?

Maybe someone in the forum will come up with a more intuitive explanation, but here's mine for now: The external magnetic field interacts with the magnetic dipole of the electron in the wire and tries to align it. However, the electron resists the alignment by emitting electromagnetic radiation, which in turn leads to a lateral deflection of the electron. In the process, the magnetic dipole of the electron also tilts out of its alignment again. The process continues as long as the magnetic field changes.

Also, do magnetic fields only induce current in loops of wire?

Quite clearly no. This phenomenon occurs in every conductor - i.e. for all freely moving charge carriers - be it a wire or a block. However, the strength of the phenomenon depends on the well-designed structure. A coil produces the greatest effect.

Answer 2

You have it the wrong way round, the changing magnetic flux induces an emf which in turn, if there is a conducting circuit, produces the induced current.

Thus the electromotive force is the driving agent which makes the charges move.

. . . . do magnetic fields only induce current in loops of wire?

Only if the circuit is conducting.

If there is a loop of wire (conductor) with a break in it (insulator) and there is a constantly increasing magnetic field within the loop (which includes the non-conducting gap) then an emf is induced in the loop.
Charges move (current) under the influence of the induced emf with the result that there is a redistribution of charges across the gap which is acting like a capacitor.
When the gap is "fully charged" (potential difference across gap equal to emf) then the transient current ceases to flow but the emf is still being induced.