Answer: 107* 10^3 C/m^2
Explanation: In order to explain this results we have to consider a spherical gaussian surface that include the cube so by using the Gaussian law we know that total electric flux is equal to Q inside/εo.
Then the flux for one face of the cube is obtained divide by 6 Q inside/εo.
Electric flux on one face= 5.68 μC/(6*εo)= 107* 10^3 C/m^2