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Physgeek64
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Homework Statement
A parallel plate capacitor is made of two flat horizontal conducting plates in a vacuum, each of area A, separated by a small gap. One plate carries a total charge 2Q, the other a total charge −Q. Find the surface charge densities on the four horizontal metal surfaces in terms of Q and A. Find the electric field between the plates, and the electric field immediately above and below the capacitor.
Homework Equations
The Attempt at a Solution
I would have though ##\sigma_1 =\sigma_2=\frac{Q}{A}## and ##\sigma_3=\sigma_4=-\frac{Q}{2A}## but the answer is ## sigma_1=\frac{Q}{2A}## ##\sigma_2=\frac{3Q}{2A}## ##\sigma_3=\frac{-3Q}{2A}## ##\sigma_4=\frac{-Q}{2A}## but i cannot see how they have got this