This is a question that comes from the EK #1 FL and they had a rather brief explanation but I think I may understand this concept and wanted to verify with you guys.
So the reason why a dipole placed between 2 parallel capacitor plates does not experience a net force even if the voltage is doubled, is because although the electric field between the 2 plates increases, there will still be an equal and opposite force being applied to both the positive and negative ends of the dipole, resulting in 0 net force.
So the reason why a dipole placed between 2 parallel capacitor plates does not experience a net force even if the voltage is doubled, is because although the electric field between the 2 plates increases, there will still be an equal and opposite force being applied to both the positive and negative ends of the dipole, resulting in 0 net force.