Necessity of charge rearragement in capacitors for equal potential differences

[animalcroc]

Consider a two identical capacitors connected in parallel and connected to a battery. The battery is removed and then a dielectric is inserted between one of the capacitors. Why will charge flow from one capacitor to the one with the dielectric? I know the "potential differences in the capacitors must be equal" but it does not make sense how that is sufficient reason to cause a charge imbalance. It seems unnatural how charge would accumulate when they naturally repel.

Can you explain this?

 

[Hootenanny]

Remember that a dielectric has a surface charge that will produce an electric field opposing the electric field of the capactior. So if you like at the negative plate more negative charges will be attracted to the surface charge on the dielectric increasing the charge on the negative plate.

 

[astrokreng]

I can provide an explanation for the necessity of charge rearrangement in capacitors for equal potential differences. When two identical capacitors are connected in parallel and connected to a battery, they share the same potential difference. This means that the charge on each capacitor is equal and opposite, resulting in a net charge of zero.

However, when a dielectric is inserted between one of the capacitors, the capacitance of that capacitor increases. This means that the charge on that capacitor must also increase in order to maintain the same potential difference. This charge increase can only come from the other capacitor, as there is no external source of charge. Therefore, charge will flow from one capacitor to the other until the potential difference between them is equalized again.

This phenomenon is a result of the natural tendency of charges to repel each other. As the charge on one capacitor increases, the repulsion between its charges becomes stronger, causing them to spread out and move to the other capacitor. This process continues until the potential difference between the two capacitors is equalized, at which point the net charge on each capacitor will once again be zero.

In summary, the necessity of charge rearrangement in capacitors for equal potential differences is a result of the fundamental principles of electrostatics and the natural behavior of charges. It is not an unnatural or arbitrary process, but rather a necessary consequence of the laws of physics.