If the distance between two parallel plates of a capacitor is \(d\), \(A\) is the area of each plate, and \(E\) is the e…
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If the distance between two parallel plates of a capacitor is \(d\), \(A\) is the area of each plate, and \(E\) is the electric field, find the energy stored in the capacitor.
(Shift I - Memory Based)
✓ Correct answer: a)
\(\frac{1}{2}{E}^{2}A{ϵ}_{0}d\)
Explanation
- The capacitance of the parallel plate capacitor is: \(C={ϵ}_{0}\frac{A}{d}\mathrm{.}\)
- Energy stored in a capacitor: \(U=\frac{1}{2}C{V}^{2}\mathrm{.}\)
- Substituting \(V=Ed\) and \(C={ϵ}_{0}\frac{A}{d}\):
- \(U=\frac{1}{2}{ϵ}_{0}\frac{A}{d}(Ed{)}^{2}=\frac{1}{2}{E}^{2}A{ϵ}_{0}d\mathrm{.}\)
Thus, the energy stored is \(\frac{1}{2}{E}^{2}A{ϵ}_{0}d\)
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