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) 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

`a. phi=q/epsi_(0)`
`q=phi xx epsi_(0) =8 xx 10^(3) xx 8.85 xx 10^(-12) =0.07 muC`
b. No, only that the net charge inside is zero.