The Magnitude of the Magnetic Field That a Long and Extremely

Multiple Choice

The magnitude of the magnetic field that a long and extremely thin current-carrying wire produces at a distance of $3.0 \mu \mathrm { m }$ from the center of the wire is $2.0 \times 10 ^ { - 3 } \mathrm {~T}$ . How much current is flowing through the wire? $\left( \mu _ { 0 } = 4 \pi \times 10 ^ { - 7 } \mathrm {~T} \cdot \mathrm { m } / \mathrm { A } \right)$

A) $19 \mathrm {~mA}$
B) $190 \mathrm {~mA}$
C) $380 \mathrm {~mA}$
D) $30 \mathrm {~mA}$