Does a constant magnetic field cause a current?

Only varying magnetic fields can create a current, either by turning the field on and off, moving the magnet or the conductor.
  • #1
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(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?
 
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  • #2
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
 
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Related to Does a constant magnetic field cause a current?

1. Does a constant magnetic field always cause a current?

No, a constant magnetic field does not always cause a current. In order for a current to be induced, there must be a change in the magnetic field, such as movement or variation in strength.

2. How does a constant magnetic field induce a current?

A constant magnetic field can induce a current through the process of electromagnetic induction. This occurs when a conductor, such as a wire, moves through the magnetic field, causing the electrons in the conductor to move and creating a current.

3. What factors affect the strength of the current induced by a constant magnetic field?

The strength of the current induced by a constant magnetic field depends on the strength of the magnetic field, the speed at which the conductor is moving, and the angle between the direction of the magnetic field and the direction of motion.

4. Can a constant magnetic field induce a current in any material?

Yes, a constant magnetic field can induce a current in any material that is capable of conducting electricity. This includes metals, as well as some non-metals such as graphite.

5. What are some practical applications of a constant magnetic field inducing a current?

Some practical applications of a constant magnetic field inducing a current include generators, motors, and transformers. These devices use electromagnetic induction to convert mechanical energy into electrical energy or vice versa.

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