Hi.. I have 2 questions ( simple once i assure you :D) in Electromagntics. 1) ""A 0.120 m long copper wire has mass of 9.02 g and is carrying a current of 5.10 A perpendicular to a uniform magnetic field. This apparatus is placed in a strong magnetic field and the wire is found to levitate. Calculate the magnetic field Strength (B)" Solution : I actually solved this one right, Fm=fg I L B = Mg B= mg/I L What i don't understand is, why do we say that Fm=Fg if the wire Levitate ? i mean... if the why Levitate, it make sense that Fm is bigger (in magnitude) then Fg... why do we equalize them ?? My second questions "Would two parallel wires carrying a current in opposite directions repel or attract one another?" I think they would repel. but i don't know why :P Thank, any help is really appreciated.