# Electric currents and Magnetic fields

1. Mar 14, 2017

### SDTK

1. The problem statement, all variables and given/known data
A Neutral copper Rod, a polarized insulator rod, and a bar magnet are arranged around a current-carrying wire.
Will the neutral copper rod, polarized insulator, and magnet remain stationary?

2. Relevant equations
does the electric field of the current carrying wire have an effect on the neutral copper rod? ie will it become polarized?

3. The attempt at a solution
(The N pole of the bar magnet is arranged so that it oriented toward the current carrying wire.) The bar magnet will rotate so that the N pole aligns with the direction of the magnetic field.

The magnetic field does not effect (cause movement of) the neutral copper rod, or the polarized insulator rod.

The insulator rod is polarized because of the current in the wire. --- I do not believe that it will not move, ... unless the the copper rod becomes polarized.... my uncertainty of how the Electric Field of the current carrying wire affects the neutral copper rod is the basis of my question--

2. Mar 15, 2017

### kuruman

Did you mean magnetic field? There is an electric field inside the current-carrying wire, but all it does is push electrons from one end to the other. I believe this question is about the effects of the magnetic field set up by the current in the wire.
Check out "diamagnetism".
Are you saying that if the current is turned off the insulator will stop being polarized? What relevant equation relates the polarization to the current?

3. May 21, 2017

### SDTK

:-) thank you, for both the comments regarding the question, and the suggestion to check out diamagnetism.