A long straight wire carries a current of π amp. The magnetic field due to it will be 5×10−5 weber/m2 at what distance from the wire (in metre) ?

104 μ0 / π 106 μ0  104 μ0  106 μ0 / π

104 μ0

Magnetic field due to a long wire : B = \(\frac{\mu_{o}}{2\pi}\) \(\frac{I}{r}\) I : current  r : distance r = \(\frac{\mu_{o}}{2\pi}\) \(\frac{I}{B}\)    = 104 μ0