Question
The electrostatic force between the metal plates of an isolated parallel capacitor C having a charge Q and area A is:

Answer

(a) independent of the distance between the plates
Explanation: $F=Q E=Q \frac{\sigma}{2 \varepsilon_0}=Q \frac{Q}{2 A \varepsilon_0}=\frac{Q^2}{2 A \varepsilon_0}$
F is independent of the distance between the plates.

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