Does a constant magnetic field cause a current?

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 3K views
x86
Gold Member
Messages
256
Reaction score
18
(1) I previously learned that a constant magnetic field causes a force on any electrons within its range. Clearly, this force would cause electrons to move. Isn't this creating a current?

(2) However, now apparently I am told that the only varying magnetic fields can create a current. I.e., turning a magnetic field on and off.

I am confused about this. Doesn't the first statement imply that a constant magnetic field can create a current?
 
Engineering news on Phys.org
hi x86

The force on a charge (electron) from a magnetic field is proportional to q x v (law of Biot-Savart). If v = 0, ( ie. the magnetic field and the electron are stationary) there is no force.

(2) However, now apparently I am told that the only varying magnetic fields can create a current. I.e., turning a magnetic field on and off.
That's correct, so ...
1) turn magnetic field on and off
2) just moving the magnet ( field)
3) or by moving the conductor in a magnetic field.

There has to be relative motion between the field and the conductor

Dave
 
Last edited:
  • Like
Likes   Reactions: x86