Ans: It is given that:
Net outward flux through surface of the box, 
For a body containing net charge a, flux is given by 
where,
Therefore, the charge 
![\[\begin{array}{l} \Rightarrow \mathrm{q}=8.854 \times 10^{-12} \times 8.0 \times 10^{3} \\ \Rightarrow \mathrm{q}=7.08 \times 10^{-8} \\ \Rightarrow \mathrm{q}=0.07 \mu \mathrm{C} \end{array}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-dbc6fd95b0011f1bcdbfe7d9545fd392_l3.png "Rendered by QuickLaTeX.com")
Careful measurement of the electric field at the surface of a black box indicate that the net outward flux through the surface of the box is 
