What magnetic field strength will levitate the 2.0 g wire in the figure

magnetic-field

#1

What magnetic field strength will levitate the 2.0 g wire in the figure(Figure 1) ? Assume that J = 1.5 A and d = 11 cm.What is the direction of the magnetic field?
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Answer:

m g = i d B

===> B = mg/id = 2e-3*9.8/1.5/0.11 = 0.119 T

direction: ouside the page.