Near the surface of the Earth there is a downward-directed electric field of 150 Vm-1. Using Gauss’s theorem, calculate the surface charge density at the Earth’s surface. Assume the Earth is a conducting medium.
At 200 m above the surface of the Earth the downward field is 100 Vm-1. Calculate the average volume charge density in the Earth’s atmosphere below 200 m.
Express your answers as an excess (or deficit) of electrons per unit area or per unit volume.