Regarding the Earth and a cloud layer 800 m above the Earth as the "plates" of a capacitor, calculate the capacitance of the Earth-cloud layer system. Assume the cloud layer has an area of 1.00 km2 and the air between the cloud and the ground is pure and dry (k=1). Assume charge build up on the cloud and on the ground until a uniform electric field of 3.00x106 N/C throughout the space between them makes the air break down and conduct electricity as a lightning bolt.
What is the maximum charge the cloud can hold?