PLEASE ANSWER FAST..... Find out the net force on charge `1`having a charge of `q` due to all other charges, given that the side of the cube is `a`.

Charge q is on the corner of a cube. If we draw imaginary cubes we will get only four corners visible to us. According to Gauss Theorem flux=EA=€/q where € is permittivity... Surface area of cube is 6a^2.Hence flux from four corners will be E6a^2=€/q. Now flux from one of the four corners is 1/4E6a^2=€/q.......Now E=F/q.Hence (3F/2)a^2=€.......F=2€/3a^2..... hoping that it will help u.Regards ROHIT.