Final answer:
The surface charge density on two conducting slabs is determined by the charge per unit area on the slabs and is not dependent on the thickness or the area of the slabs.
Step-by-step explanation:
The surface charge density on two conducting slabs does not depend on the thickness of the slabs or their area. Instead, it is determined by the amount of charge per unit area on the surfaces of the slabs. In the case of two thin parallel conducting plates, such as those discussed in the materials provided, the charge density is calculated by dividing the net charge on a plate by the area of the plate. This is particularly straightforward if the plates are very large relative to their separation, as they will form a parallel-plate capacitor configuration, with charges on opposing plates being equal and opposite.
When dealing with conductive surfaces, if the plates are connected to a battery or have a fixed charge distribution, the surface charge density will be uniform on each conductive surface, regardless of the slab's physical dimensions. This is because charges on a conductor redistribute themselves until they reach equilibrium, where the surface is at a constant potential, leading to a uniform surface charge density.