Assume the magnitude of the magnetic field outside a sphere of radius $R$ is $B=B_{0}(R / r)^{2}$ , where $B_{0}$ is a constant. Determine the total energy stored in the magnetic field outside the sphere and evaluate your result for $B_{0}=$ $5.00 \times 10^{-5} \mathrm{T}$ and $R=6.00 \times 10^{6} \mathrm{m},$ values appropriate for the Earth's magnetic field.