I have a general gauss' law/electric field question. In calculating the electric field of a cylindrical shape, gauss' law can be applied to find that the Electric field only points aways from the surface of the cylinder (aka, in the s-hat direction). But this means that there are no field lines directed along the cylinder.....why isnt there a field line that points directly up or down along the z axis? For a finite cylinder, this would make sense to me. However, whenever you are calculating the E field via gauss' law, you neglect the surface area of the circles in the cylinder.....can someone please clarify why this is? I have taken it for granted for a long time but never really understood.... Thanks in advance!