Answer:
A) a scientific theory or principle
Explanation:
A Theory or principle has to explain different observations for a specific phenomenon. Theories are tested in base of new data to see if they can fit with all the new variations. They gain more acceptance in the scientific world if they predict in a correct way the result of many observations.
For example the uncertainty principle which state that the position and the momentum of a particle can not be known at the same time. Many experiments that aim to test the Uncertainty principle demonstrated this property, but tests are currently being done with other variations to see if the principle still fits with them.
Answer:
1.55 m
Explanation:
The potential produced by a point charge, is inversely proportional to the distance from the charge to the point where the potential is being calculated, as follows:

As it only depends from the distance r, we can conclude that if the potential is the same for any point to a distance r from the point charge, the equipotencial surface must be a sphere of radius r.
Replacing q = +1.7*10⁻⁸ C, and k = 9*10⁹ N*m²/C², and V, by 120 V and 54 V, we can find the distance from the charge, to the points where we are calculating the potential V, as follows:


The distance between both points, is just the difference between the radius of both spheres, as follows:
r₂ - r₁ = 1.55 m