Coulomb Balance Lab Report

            
             The goal of the experiment was to demonstrate the fundamental joys known to many a physicist of Coulomb's law through comparative analysis of electrostatic force, potential, and capacitance. We completed this goal by using a torsion balance to measure the properties of such an event. We then completed the analysis to find that after making linear and angular measurements of the separation, that the voltage varied over the spheres depending on the distance in a uniform ration.
             Theory and Background:.
             If one lesson in electrostatic forces doesnt cover Coulomb's law then you have been served a great injustice. Coulomb's law is one of the fundamental principles that one needs to know when comparing two points (i.e. Q1, Q2) that are separated by a distance of r. This law is represented with the equation:.
             F=kQ0Q1/r2.
             Where K=1/4 •0 and •0 is the permitivity of free space (•0 =8.85 * 10-12 C2/Nm2).
             In addition, at a large distance such spheres, when conducting, should vary with the equation, 1/r2. Of course when the sphere are moved into closer proximity the charges then redistribute to minimize potential energy. If by chance the charge of the two spheres are the same, then they will repel, in turn effectively separating the charge distributions, reducing the measured force. This reduction of force potential can be calculated as a function of r:.
             f =1-4(a/r)3.
             Where a is the reduction of their radii. This in turn will produce the forge of:.
             Fcoulomb = [ 1-4(a/r)3] (kQ0Q1/r2).
             In addition, since the sphere is a conducting capacitor, the charge will be Q=CV. When this is isolated, the capacitance of the sphere can be established by the equation C=1/4 •0a, where a is the radius of the sphere. When combined, they in turn produce a charge overall of the sphere determined by Q=CV=4 •0aV.
             Procedure:.
             On a day that appeared it was never going to end, and only get better by visiting Rockefeller the Physics Department hangout my colleague and I set out to expand our minds and the possibilities of the world as we entered the fourth floor of such a monumental edifice to higher education.