Final answer:
The charges in question do not have the same magnitude; charges of the same sign exert equal and opposite forces, and the number of field lines is indicative of charge magnitude. Moreover, the electric potential from multiple charges is the sum of individual potentials, and the basic unit of charge for electrons and protons is central to understanding charge in natural phenomena.
Step-by-step explanation:
Considering the provided information, it appears that the charges do not all have the same magnitude. In this scenario, charges of the same sign (+q and +q or -q and -q) placed a distance r apart will exert equal but opposite forces on each other, adhering to Coulomb's Law, which states that the magnitude of the force between two charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. The net electric field along the x-axis will vanish at some point due to the superposition principle, as electric fields are vector quantities and can cancel each other when equal and opposite.
The assertion that the number of field lines is proportional to the magnitude of the charge indicates that a charge of 2q will have twice as many lines as a charge of q. If the field diagram for objects R, S, and T shows that S has twice as many lines as R and T, this would suggest that the magnitude of S's charge is about twice that of R's and T's. Moreover, electric potential from a group of charges is indeed the sum of the potentials from each individual charge, making the statement true.
The characteristic charge of electrons and protons is 1.60×10-19 C, and all natural charges are multiples of this fundamental unit. Lastly, when two parallel metal plates are charged with opposite charges of the same magnitude, they create an electric field between them. The electric potential created by these plates is the sum of the potentials due to each plate, echoing the principle that potential is additive.