Question

Imagine that a cloud passes over a certain spot on the surface of the Earth and that you record a vertical electric field of 100 Volts/meter at that spot. The bottom of the cloud is exactly 300 meters above the surface of the Earth and the top of the cloud is 300 meters above the bottom of the cloud (i.e, 600 meters from the surface of the Earth). Assume that the cloud is electrically neutral but has a charge +q at its top and -q at the bottom. Estimate the magnitude of the charge q and the external electrical force (stating both direction and magnitude) on the cloud. You may assume there are no charges in the atmosphere other than those in the cloud and that the ground is at V=0.

Answer 1