A long,straight wire is fixed horizontally and carries a current of 50.0 A.A second wire having linear mass density 1.0×10−4 kg m−1 is placed parallel to and directly above this wire at separation of 5.0 mm.What current should this second wire carry such that the magnetic repulsion can balance its weight ?
According to question μ0i1i22πd=dFdl
2×10−7×50×i25×10−3=1×10−4×9.8
i2=9.8×10−720×10−7A
0.49 A in opposite direction.