What is the equation for the electric field caused by an infinite plate of charge? Is it sigma/2epsilon0? So does that mean that the distance from a point to the plate doesn't matter in computing the E field? How does this change if a solid conducting slab with significant thickness (2 cm) is used? I know that the charges should build up on each side, with half of the charges on each side, so is that treated then as 2 plate charges?