Lighting strike: Storm clouds build up large negative charges that dwell in a charge center. Suppose a storm cloud has -25 C in a charge center located 10 km above the ground. The negative charge center attracts an equal amount of positive charge that is spread on the ground below the cloud. The charge center and the ground function as a charged capacitor, with a potential difference of 4 x 10^8 V. The large electric field between these two electrodes may ionize the air leading to a conducting path between the cloud and the ground.

a) What is the magnitude of the electric field between the charge center and the ground?

b) What is the capacitance of the charge center ground system?

c) If the cloud transfers all of its charge to the ground via several rapid lighting flashes lasting a total of 1 s what is the average power.