The insulation property of air breaks down at $E=3\times {10}^6 \mathrm{V} {\mathrm{m}}^{-1}.$ The maximum charge that can be given to a sphere of diameter $5 \mathrm{m}$ is approximately (in coulombs)

A metallic solid sphere is placed in a uniform electric field.The lines of force follow the path $\left(s\right)$ shown in figure as

The figure shows some of the electric field lines corresponding to an electric field. The figure suggests