Question

derive and expression for the energy density of a parallel plate capacitor.

Answer 1

We know that, for a capacitor,
U = ½CV2
Here, C = EoA/d and V = Ed
Therefore, U = ½(EoA/d)*(Ed)2
or, U = ½EoE2V (where V=Ad)
Hence the required expression for the energy density of a parallel plate capacitor is given by
U/V = ½EoE2


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