A solid metal cube of edge length $2\mathrm{ }\mathrm{cm}$ is moving in the positive $\mathrm{y}$-direction, at a constant speed of $6\mathrm{ }\mathrm{m} {\mathrm{s}}^{-1}$. There is a uniform magnetic field of $\text{0.1}\mathrm{ }\mathrm{T}$ in the positive $\mathrm{z}$-direction. The potential difference between the two faces of the cube, perpendicular to the $\mathrm{x}$-axis, is