Q27. A 2 A current carrying straight metal wire of resistance $1 \Omega$, resistivity $2 \times 10 ^ { - 6 } \Omega \mathrm {~m}$, area of cross-section $10 \mathrm {~mm} ^ { 2 }$ and mass 500 g is suspended horizontally in mid air by applying a uniform magnetic field $\vec { B }$. The magnitude of $B$ is $\_\_\_\_$ $\times 10 ^ { - 1 } \mathrm {~T}$ (given, $\mathrm { g } = 10 \mathrm {~m} / \mathrm { s } ^ { 2 }$ ).