In lightning storms, the potential difference between the earth and the bottom of the thunderclouds can be as high as 35000000 V.The bottoms of the thunderclouds are typically 1500 m above the earth, and can have an area of 110 km^2. Modelling the earth-cloud system as a huge capacitor,calculate

a)the capacitence of the earth -cloud system,
b)the charge stored in the capacitor and
c)the energy stored in the capacitor.

1 answer

a) C = epsilon*A/d = 0.65*10^-6 F
b) Q = CV = 22.7 coulombs
c) E = (1/2) C V^2 = 400*10^6 J

A is the cloud base area, 110*10^6 m^2
d = 1500 m "plate separation"
epsilon = 8.85*10^-12 Farad/m

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