# Q & A: magnetic forces on conductors

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Most recent answer: 07/11/2019
Q:
Why there will be no force of magnetic field when a conductor which is not carrying current in placed in a uniform magnetic field?. Please give theoretical explanation to it. Since Electrons are considered the moving charges in atoms. Electrons generate magnetic fields perpendicular to their planes of rotation.The resultant of electron magnetic field and the uniform magnetic field wont exert any force on the conductor? Please give theoretical answer to this.
- chandra (age 30)
Bengaluru,karnataka,india
A:

You're right that each electron has a magnetic moment. That means that there's some potential energy that depends on the dot product of the moment and the field. If the field is uniform, that potential energy won't depende on position. Therefore it gives no force.

The electrons are also moving, so each one does feel a Lorentz force proportional to vxB. Since there are just as many electrons with velocity near -v as near v, those forces average to zero.

Mike W.

(published on 07/11/2019)