Question

How do i figure out the direction for this problem: A wire having a mass per unit length of 0.500 g/cm carries a 2.00 A current horizontally to the south. What is the direction of the minimum magnetic field needed to lift this wire vertically upward?

Answer 1

The minimum magnetic field would be oriented perpendicular to the wire.

If current I is to the south, the force on the wire will be up if B is pointing east.

(right hand rule, I x B)