The diagram in Figure 1 depicts a thundercloud, having its negatively charged base at an altitude of 1500 m above the earth. The base area of the cloud is 90 km. The cloud is about to discharge a lightning bolt. Experimental measurements indicate that discharge occurs when the electric field reaches a value of about 400 kV/m. (a) (b) (c) (d) Determine the voltage between the cloud and earth before discharge If you model the cloud-earth system as a parallel plate capacitor what is its capacitance ? Calculate the negative charge stored on the cloud just before discharge Calculate the total stored electric energy before the lightning strike If the discharge lasts 100 ms, determine the average power developed during the stroke. Surface of earth ++ ++ + + + + Cloud + + + + + + + + 1500 m