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 `8.0 xx 10^(3)N*m^(2)*C^(-1)`.
(a) What is the net charge inside the box?
(b) If the net outward flux through the surface of the box where zero, could you conclude that there where no charges inside the box? Why or why not ?

Explanation

Flux `=(q)/(in_(0))`
`therefore q=in_(0) xx "flux"=8.854xx10^(-12)xx8xx10^(3)C`
`=0.07mu C`
(b)It can only be said that net charge inside the box is zero.