I was doing a problem: An infinite conducting plane has a uniform surface charge density of 30 μC m‾². Find the electric field strength 7.0 mm from the plane. so we can use a gaussian surface (e.g a cylinder), and come to the conclusion that E = 30 μ / ε but that got me thinking, doesn't the electric field strength depend on distance? I understand that the electric field within the gaussian surface is 0, and that only the top of the gaussian surface we used (cylinder) would have flux passing through it. But from my working, wouldn't this mean if we were finding the electric field strength at any distance from the conducting plane e.g 100 metres away , E would still be the same? How does that even work? Thanks for your time!