As a crude model for lightning, consider the ground to be oneplate of a parallel-plate capacitor and a cloud at an altitude of470 m to be the other plate. Assumethe surface area of the cloud to be the same as the area of asquare that is 0.40 km on aside.
(a) What is the capacitance of thiscapacitor?
(b) How much charge can the cloud hold before the dielectricstrength of the air is exceeded and a spark (lightning) results?