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Asked in GSEB Board July 2017 · Energy stored and energy density
Idea: charging a capacitor means moving charge from one plate to the other against the electric field that builds up between them.
The work done by the source in doing this is stored as energy of that electric field.
Energy density of the field: u = 1/2ε₀E²; over the volume Ad between the plates this gives 1/2ε₀E²Ad = 1/2CV².
(While charging through the resistor, an equal amount of energy is lost as heat in R; the stored part is in the field.)
So the energy is stored in the electric field.
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