Can you explain the charged slab CyberTutor problem?
These can be done with the Gauss’ Law how-to; the trick is to pick the right surfaces. For part B: pick a Gaussian box which sticks out of the surface on either side, with end surfaces parallel to the slab surface. The electric field is perpendicular to the slab surface. The flux through the sides of the Gaussian box is therefore zero. The flux through each end of the box is , where is the area of the Gaussian box. So the LHS of Gauss Law is .
