In a certain experiment, we place two metal plates of area A parallel to each other and separated by a distance d to form a capacitor. The copper disks are mounted on nonconducting stands in a dry room which does not allow the conduction of charge through the air. The two plates are connected with wires to the opposite ends of a DC cell. The capacitance of such a device is given by
In Experiment 1 we place two copper circular disks of radius R1 a distance d1 apart and connect them to a battery which produces a potential ΔVbat. This produces a positive charge Q1 on one of the plates and an electric field E1 between the plates.
In Experiment 2 we use two copper circular disks of the same radius (R1) and place them three times as far apart (3d1) as in Experiment 1. Again, the two disks are connected to the opposite ends of the same battery.
In Experiment 3 we reproduce the setup in Experiment 1. Then the wires are removed from the copper plates. The copper plates are carefully separated to a new distance 2d1.
An alpha particle is a bare helium-4 nucleus. If an alpha particle is placed between the plates in Experiment 1, how would the electric force on it compare to the electric force on a proton?