How Is the Magnetic Field Calculated to Levitate a Wire Carrying Current?

[roam]

Homework Statement

A straight piece of wire of mass 0.0050 kg and length 0.600 m lies horizontally and carries an electrical current of I = 0.800 A in the direction E to W . What is the direction and magnitude of the magnetic field required to produce an upward force on the wire that exactly cancels its weight?

Homework Equations

The Attempt at a Solution

The direction is South and the magnitude of the magnetic field is 0.102 T. How did they calculate this? What principles and formulas are required here?

 

[Quinzio]

http://en.wikipedia.org/wiki/Lorentz_force
Go at:
Force on a current-carrying wire

 

[roam]

Okay. Using this equation for force on a segment of current-carrying wire in a uniform magnetic fields F=ILxB, how would you relate this to the mass of the wire?

 

[roam]

And how can I work out the inductance L? All the equations I know for L are for a solenoid...

 

[axdv]

You may have figured this already, but F = I (L x B) where F=ma & 'L' is length (not inductance)