Careful measurement of the electric field at the surface of a black box indicates that the net outward flux through the surface of the box is `8.0xx10^(3) Nm^(2)//C` (a) what is the net charge inside the box ? (b) If the net outward flux through the surface of the box were zero, could you conclude that there were no charges inside the box ? Why or why not?

Explanation

Using the concept of Gauss's theorem
Given net outward flux `f=("change")/e_0=q/e_0 implies q=e_0 f=8.854 times 10^-12 times 8 times 10^3`
From Gauss's theorem `q=0.07 times 10^-6 C=0.07 mu C` The flux is outward hence the charge is positive in nature.