(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

what is the approx electric field 1cm above a typical sheet of paper with a surface charge density of sigma = 45 nC/m^2?

2. Relevant equations

electric field E = sigma/epsilon_0 where epsilon_0 = 8.85*10^-12

E = kq/r^2 where k = 9*10^9, r is distance in meters

assume paper is charged sheet, then E = sigma/2*epsilon_0

3. The attempt at a solution

i assumed that 1 cm is so small that the distance is insignificant and could be ignored, i think this is why i got it wrong. anyways...

E = sigma/epsilon_0 = (45*10^-8)/(8.85*10^-12) = 50847 N/C

it is wrong, how do i factor in the distance? should i have used the charged sheet formula instead or the general equation (the first one)?

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# Homework Help: Gauss law - electric field

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