%3Cp%20class%3D%22c1%22%3EA%20typical%20thundercloud%20has%20a%20layer%20of%20po
ID: 3899983 • Letter: #
Question
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a) direction of electric field from upper layer to lower layer of charge.
b)
cross sectional area of the disk, A = pi*r^2 = 3.14*(5*10^3)^2 = 7.85*10^7 m^2
let q is the chrge need to lighteing occure
E = (Q+q)/(A*epsilon)
1*10^5 = (40+q)/(7.85*10^7*8.854*10^-12)
q = 1*10^5*7.85*10^7*8.854*10^-12 - 40
= 29.5 C
c) when ligheting accurs total charge, Qnet = Q+q = 69.5 C
U = 0.5*epsilon*E^2*(A*d)
= 0.5*8.854*10^-12*(10^5)^2*(7.85*10^7*1000)
= 3.475*10^9 J
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