Answer:
The amount of charge at the center is -132.7 nC
Solution:
As per the question:
Electric flux from one face of cube, [tex]\phi_{E} = - 2.5 kN.m^{2}/C[/tex]
Edge, a = 19cm
Since, a cube has six faces, thus total flux from all the 6 faces = [tex]6\times (-2.5) = - 15 kN.m^{2}/C[/tex]
Also, from Gauss' law:
[tex]\phi_{E,net} = \frac{1}{\epsilon_{o}}Q_{enc}[/tex]
[tex]Q_{enc} = 8.85\times 10^{- 12}\times - 15\times 10^{3}[/tex]
[tex]Q_{enc} = - 132.7 nC[/tex]