A straight wire $\mathrm{AB}$ of mass $40 \mathrm{~g}$ and length $50 \mathrm{~cm}$ is suspended by a pair of flexible leads in uniform magnetic field of magnitude $0.40 \mathrm{~T}$ as shown in the figure. The magnitude of the current required in the wire to remove the tension in the supporting leads is ___________ A.

$\left(\right.$ Take $g=10 \mathrm{~ms}^{-2}$ ).